CA2220480A1 - Multi-frequency remote communications system - Google Patents
Multi-frequency remote communications system Download PDFInfo
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- CA2220480A1 CA2220480A1 CA002220480A CA2220480A CA2220480A1 CA 2220480 A1 CA2220480 A1 CA 2220480A1 CA 002220480 A CA002220480 A CA 002220480A CA 2220480 A CA2220480 A CA 2220480A CA 2220480 A1 CA2220480 A1 CA 2220480A1
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- 238000004891 communication Methods 0.000 title claims abstract description 67
- 230000006854 communication Effects 0.000 title claims abstract description 67
- 239000002184 metal Substances 0.000 claims abstract description 6
- 229910052751 metal Inorganic materials 0.000 claims abstract description 6
- 230000005540 biological transmission Effects 0.000 abstract description 10
- 238000012546 transfer Methods 0.000 abstract description 2
- 238000000034 method Methods 0.000 description 12
- 239000012530 fluid Substances 0.000 description 8
- 230000006870 function Effects 0.000 description 6
- 238000002955 isolation Methods 0.000 description 5
- 230000008439 repair process Effects 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 238000012790 confirmation Methods 0.000 description 3
- 230000008878 coupling Effects 0.000 description 3
- 238000010168 coupling process Methods 0.000 description 3
- 238000005859 coupling reaction Methods 0.000 description 3
- 230000004044 response Effects 0.000 description 3
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q9/00—Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B13/00—Transmission systems characterised by the medium used for transmission, not provided for in groups H04B3/00 - H04B11/00
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B5/00—Near-field transmission systems, e.g. inductive or capacitive transmission systems
- H04B5/20—Near-field transmission systems, e.g. inductive or capacitive transmission systems characterised by the transmission technique; characterised by the transmission medium
- H04B5/24—Inductive coupling
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2209/00—Arrangements in telecontrol or telemetry systems
- H04Q2209/40—Arrangements in telecontrol or telemetry systems using a wireless architecture
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
- Selective Calling Equipment (AREA)
Abstract
This invention relates to remote two-way data communication between units through the wall of a pipeline, storage tank or other containment vessel. The efficient control of devices deployed within metal containment vessels such as pipelines or storage tanks is difficult without intrusion into the vessel by wires. Prior art systems have been limited in range and speed of data transfer. The present invention comprises a control unit located remote from the containment vessel and capable of two-way RF communication with a translator unit located on the outside of the containment vessel. The translator unit is capable of two-way RF communication with the control unit and two-way EM communication at low frequency with a command unit attached to a device located inside the containment vessel. Signals sent from the control unit to the translator unit are converted to low frequency EM and transmitted through the wall of the containment vessel to the command unit for controlling the device inside the vessel.
Signals and data from the device inside the vessel are sent by low frequency EM back through the vessel wall to the translator where they are converted to RF for transmission to the hand held control unit located remote from the containment vessel.
Signals and data from the device inside the vessel are sent by low frequency EM back through the vessel wall to the translator where they are converted to RF for transmission to the hand held control unit located remote from the containment vessel.
Description
MULTI-FREQUENCY REMOTE COMMUNICATION SYSTEM
FIELD OF THE INVENTION
This invention relates to remote 2-way data communication between units through the wall of a pipeline, storage tank or other containment vessel.
BACKGROUND OF THE INVENTION
It is often necessary to transmit signals and to send data between control units on the outside of metal containment vessels such as pipelines or storage tanks and pipeline tools or other devices operating inside such containment vessels, without intruding into the containment vessel itself. This can be especially advantageous when a liquid or gaseous medium is enclosed within the containment vessel.
One example of a device requiring a communication system as disclosed by the present invention is a pipeline packer or isolation tool used to isolate sections of pipe for repair or replacement. The packer is propelled to the designated location using the flow of product in the pipeline with the packer being tracked using known techniques. Upon reaching the desired location, fluid flow in the line is terminated and the packer is activated by a signal from the operator to form a seal against the inner pipeline wall. On completion of the repair, the operator transmits another signal to release the packer which is then moved away by resuming the flow of pipeline product for removal. Some isolation devices can perform multiple functions while contained within the pipeline and thus require a series of control signals to be transmitted from an operator outside the pipeline to activate each function. In addition, these devices may generate data which then must be communicated to the outside.
In the past, various devices and methods have been used in an effort to transmit signals and data through the metal wall of a containment vessel such as a pipeline or storage tank.
Some of these techniques relied upon radioactive sources, sonic frequencies, or wires which may intrude into the containment vessel or pipeline. These methods were hampered by problems associated with obtaining and containing radioactive sources, limited range and data speed, and impracticalities associated with running wires into pipelines or tanks at remote distances.
Some efforts have also been made to send data using a low band of electromagnetic radiation (EM) in the frequency range of 22hz, however, this method has been used only for sending signals in one direction to locate and track pipeline pigs and has never been used for two-way communication of data signals.
This method did not employ dual RF/EM communication and was severely hampered by the slow speed of data transfer and a limited transmission range.
It would be advantageous to provide a communications system that could transmit and receive signals and data at high rates of speed between devices located within metal containment vessels such as pipelines or storage tanks and an operator located some distance away without intruding into the containment vessel. It would also be advantageous if this communications system could be programmed to operate at different frequencies to take advantage of local conditions offering the least traffic or extraneous interference.
Accordingly, it is a general object of the present invention to provide a multi-frequency remote communication system that is useful for transmitting and receiving signals and data to and from devices located within metal containment units such as pipelines or storage tanks without intruding into the containment vessel and without removing the device from the vessel.
It is a also an object of the present invention to provide a multi-frequency remote communication system that can send and r~ceive signals at high rates of speed over relatively large distances.
It is a further object of the present invention to provide a multi-frequency re~ote communication system that can be programmed to operate at different frequencies in order to adapt and take advantage of local conditions offering the least amount of traffic or extraneous interference.
SUMMARY OF THE lNv~N-lION
The present invention comprises a communications system consisting of three components, a control unit, a translator unit and a command unit. The control unit is located remote from the containment vessel and is capable of two-way communication at radio frequencies (RF) with a translator unit located on the outside of the containment vessel. The translator unit is capable of two-way RF communication with the control unit and two-way electromagnetic (EM) communication at low frequency through the wall of the containment vessel with a command unit attached to a device located inside the containment vessel. The translator unit converts RF signals to 15 EM signals and EM signals back to RF signals.
Signals for controlling a device located inside a containment vessel are transmitted by RF from the control unit to the translator unit where they are converted to low frequency EM signals and transmitted through the wall of the vessel to the command unit. Signals and data from the command unit are transmitted by low frequency EM from the command unit through the wall of the vessel to the translator unit where they are converted to RF signals and transmitted to the control unit.
According to the present invention there is provided a 25 multi-frequency remote communication system comprising a control unit capable of two-way radio frequency communication, a translator unit capable of both two-way radio frequency communication and two-way low frequency electromagnetic communication, and an electronic command unit capable of two way low frequency electromagnetic communication.
Some of the many advantages associated with the communication system of the present invention are as follows.
First is that the system is useful for sending and receiving signals and data to and from devices located within steel 35 containment units such as pipelines or storage tanks. Second, the system can send and receive signals at high rates of speed and over relatively large distances. Third, is that the system can be programmed to operate at different frequencies in order to adapt and take advantage of local conditions offering the least amount of traffic or extraneous interference.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention will now be described in greater detail and will be better understood when read in conjunction with the accompanying drawing, in which:
Figure 1 is a schematic representation of one embodiment of the present invention showing possible positioning of the three communication units;
Figure 2 is an electronic operations block diagram for the present invention.
DETAILED DESCRIPTION
For the purposes of illustration, the present invention is described with reference to use in a pipeline. It will be appreciated, however, that the communications system and the techniques described herein may be adapted for use with any suitable containment vessel such as storage tanks, bins, railway cars, tanker trucks, etc.
Referring to Fig. 1, a pipeline tool 20, is placed inside a pipeline 5 and moved along by the flow of product in the pipeline to a desired location.
A multi-frequency remote communication system includes a control unit 30 located remote from the pipeline 5.
Multi-frequency remote communication system 1 also includes a translator unit 40 located on the outside surface of the pipeline wall 10 near the location of pipeline tool 20 deployed inside pipeline 5. Control unit 30 may be located at a distance of up 2000 meters (6562 feet) from translator unit 40 depending on terrain, and may be hand held. Control unit 30 and translator unit 40 are designed for mutual two-way radio frequency (RF) communication. Multi-frequency remote 3 5 communication system 1 further includes an electronic command unit 50 attached to pipeline tool 20 located inside pipeline 5.
Command unit 50 and translator unit 40 are designed for mutual two-way electromagnetic (EM) communication at low frequency through pipeline wall 10. The working distance between translator unit 40 and command unit 50 can range up to 3.66 meters (12 feet) depending upon the thickness of pipeline wall 10 and the nature of the product within the pipeline 5.
Translator unit 40 also performs two-way translation of RF signals to low frequency EM signals and of low frequency EM
signals and data to RF signals and data.
Electronic command unit 50 controls pipeline tool 20 by responding to commands sent by control unit 30 and translator unit 40.
The operation of one embodiment of the present invention will now be described in detail with reference once again to Figure 1. RF signals 35 are transmitted from control unit 30 to translator unit 40. Translator unit 40 receives RF
signals 35 from control unit 30 and converts them to low frequency EM signals 45. Translator unit 40 transmits low frequency EM signals 45 through pipeline wall 10 to electronic command unit 50 attached to pipeline tool 20 located inside pipeline 5. Electronic command unit 50 receives low frequency EM signals from translator unit 40 for controlling pipeline tool 20 and transmits data 46 received from pipeline tool 20, through the wall of pipeline 10 to translator unit 40 located on the outside of the pipeline wall. EM signals 46 are received by translator unit 40 and converted to RF signals 36 which are transmitted by translator unit 40 to control unit 30. Control unit 30 receives RF signals 36 from translator unit 40.
The penetrating characteristics of EM frequencies are significantly increased as the frequency is lowered, however, at low EM frequencies the ability to carry data at a usable speed is considerably reduced. Frequencies in the range of 22hz have greater penetrating ability when compared to frequencies in the range of 97hz, however, data transmission speed of frequencies in the range of 22Mhz is severely limited.
The frequency of EM signals 45 and 46 transmitted through pipeline wall 10 between translator unit 40 and command unit 50 is programmable within a range between 75hz and 110hz.
At these frequencies, the data handling speed is in the range of 20 to 30 baud, using 8 data bits, 1 start bit and 1 stop bit.
In a preferred embodiment of the present invention the optimum operating frequency has been found to be 97.8hz.
The frequency of RF signals 35 and 36 transmitted between control unit 30 and translator unit 40 is programmable within a range between 450Mhz and 470Mhz. To determine the most advantageous frequency for RF signals 35 and 36, the radio frequency band of the electromagnetic spectrum is monitored and the frequency having the least amount of traffic and providing the least amount of extraneous interference is selected.
An example of the operation of multi-frequency remote communication system 1 will now be described in relation to the operation and control of a pipeline packer or isolation tool (tool) of the kind described in our copending International Application PCT/CA97/00055. Generally, multi-frequency remote communication system 1 is used to send operating instructions to and receive data from the tool. The operating instructions relate to the various amperages, force factorsj and voltages at which it is desired that the tool operate. Once the tool has received an instruction via multi-frequency remote communication system 1 it will request confirmation of the command and will not carry out any action until confirmation has been received and a special code is entered. This process of data transmission and confirmation, back and forth between the tool and control unit 30, takes place for each command sent to the tool. In return, the tool sends data, via multi-frequency remote communication system 1, relating to the remaining battery voltage, which battery pack is in use, amount of amperage each motor is drawing, amount of force being applied to pipeline wall 10 and up and downstream pipeline pressure. This type of data will normally be transmitted by the tool on a continuous basis.
Once the tool reaches programmed force and amperage constants it will automatically shut down. During an operation, or at any time while the tool is holding pipeline pressure, should the force factor fall below the lower programmed limits, the motors will automatically restart and return the tool to the proper force factor. At the same time, the tool will constantly transmit data relating to is current status and function. An emergency halt command can be issued through multi-frequency remote communication system 1 at any time should the operator deem it necessary.
Isolation tools are normally used in pairs to close off a section of an active pipeline to allow replacement of a corroded or damaged section. This saves the time and great expense of shutting down the complete pipeline. Isolation tools have been in use generally for a number of years. However, with the present system, isotools can be instructed to perform tasks and feed back information. The system is remotely controlled using radio and electromagnetic coupling as the communications methods. This also means that the operator need not be close to the pipeline.
System Overview The system is divided into three units shown diagrammatically in Figure 2:
1) Isotool Command Unit 50 2) Base Station Translator 40 3) Hand-held control unit 30 Each isotool has duplicate electromagnetic communi-cations systems and microcontrollers known as the Main and Secondary Unset systems 51 and 52 respectively. The electronics for each are totally separate and there is also a separate battery pack 59 for the Secondary Unset system. This is a back-up system and is only meant to be used to unset the isotool in the event of failure in some part of the Main system. Removal of a failed isotool when in the pipeline locked in position would be a very expensive procedure and would requlre draining of a section of pipeline. During normal operation of the isotool the Secondary Unset system is polled to ensure that it is functioning. Should any problem be detected, the isotool will be taken out of service and flown down the pipeline until it can be removed at a convenient point.
Hand-held control unit 30 uses a radio link to communicate with the translator 40. The translator is used as a signal repeater between the control unit and the isotool command unit 50. Because of the severe attenuation of radio waves through steel piping, electromagnetic coupling is used to send and receive signals from the isotool.
In a typical set-up there will be two isotools, two translators and one or two control units. It is possible to control two isotools with one control unit although this will probably not be done.
1) Isotool Command Unit Usually two isotools are inserted into a pipeline when some repair work is necessary. Each isotool drags a large battery pack behind it which provides all its power. They flow along in the pipeline fluid (whatever it may be) until the faulty section of pipeline is reached. At that time the fluid flow is halted. The exact position of the isotool in the pipeline can be determined by receiving an electromagnetic pulsing signal from the unit allowing exact placement. As mentioned above, the isotool has two independent electronic systems. Each electronics system consists of nine printed circuit boards mounted in a 6.75" diameter module. Connectors carry the power and signals between the boards. A functional description of each board follows below.
In the stack, the boards are arranged in the following order from bottom to top:
1) Main and Secondary Unset Motor Controls.
2) Bypass Motor Controls.
3) Main Microcontroller.
FIELD OF THE INVENTION
This invention relates to remote 2-way data communication between units through the wall of a pipeline, storage tank or other containment vessel.
BACKGROUND OF THE INVENTION
It is often necessary to transmit signals and to send data between control units on the outside of metal containment vessels such as pipelines or storage tanks and pipeline tools or other devices operating inside such containment vessels, without intruding into the containment vessel itself. This can be especially advantageous when a liquid or gaseous medium is enclosed within the containment vessel.
One example of a device requiring a communication system as disclosed by the present invention is a pipeline packer or isolation tool used to isolate sections of pipe for repair or replacement. The packer is propelled to the designated location using the flow of product in the pipeline with the packer being tracked using known techniques. Upon reaching the desired location, fluid flow in the line is terminated and the packer is activated by a signal from the operator to form a seal against the inner pipeline wall. On completion of the repair, the operator transmits another signal to release the packer which is then moved away by resuming the flow of pipeline product for removal. Some isolation devices can perform multiple functions while contained within the pipeline and thus require a series of control signals to be transmitted from an operator outside the pipeline to activate each function. In addition, these devices may generate data which then must be communicated to the outside.
In the past, various devices and methods have been used in an effort to transmit signals and data through the metal wall of a containment vessel such as a pipeline or storage tank.
Some of these techniques relied upon radioactive sources, sonic frequencies, or wires which may intrude into the containment vessel or pipeline. These methods were hampered by problems associated with obtaining and containing radioactive sources, limited range and data speed, and impracticalities associated with running wires into pipelines or tanks at remote distances.
Some efforts have also been made to send data using a low band of electromagnetic radiation (EM) in the frequency range of 22hz, however, this method has been used only for sending signals in one direction to locate and track pipeline pigs and has never been used for two-way communication of data signals.
This method did not employ dual RF/EM communication and was severely hampered by the slow speed of data transfer and a limited transmission range.
It would be advantageous to provide a communications system that could transmit and receive signals and data at high rates of speed between devices located within metal containment vessels such as pipelines or storage tanks and an operator located some distance away without intruding into the containment vessel. It would also be advantageous if this communications system could be programmed to operate at different frequencies to take advantage of local conditions offering the least traffic or extraneous interference.
Accordingly, it is a general object of the present invention to provide a multi-frequency remote communication system that is useful for transmitting and receiving signals and data to and from devices located within metal containment units such as pipelines or storage tanks without intruding into the containment vessel and without removing the device from the vessel.
It is a also an object of the present invention to provide a multi-frequency remote communication system that can send and r~ceive signals at high rates of speed over relatively large distances.
It is a further object of the present invention to provide a multi-frequency re~ote communication system that can be programmed to operate at different frequencies in order to adapt and take advantage of local conditions offering the least amount of traffic or extraneous interference.
SUMMARY OF THE lNv~N-lION
The present invention comprises a communications system consisting of three components, a control unit, a translator unit and a command unit. The control unit is located remote from the containment vessel and is capable of two-way communication at radio frequencies (RF) with a translator unit located on the outside of the containment vessel. The translator unit is capable of two-way RF communication with the control unit and two-way electromagnetic (EM) communication at low frequency through the wall of the containment vessel with a command unit attached to a device located inside the containment vessel. The translator unit converts RF signals to 15 EM signals and EM signals back to RF signals.
Signals for controlling a device located inside a containment vessel are transmitted by RF from the control unit to the translator unit where they are converted to low frequency EM signals and transmitted through the wall of the vessel to the command unit. Signals and data from the command unit are transmitted by low frequency EM from the command unit through the wall of the vessel to the translator unit where they are converted to RF signals and transmitted to the control unit.
According to the present invention there is provided a 25 multi-frequency remote communication system comprising a control unit capable of two-way radio frequency communication, a translator unit capable of both two-way radio frequency communication and two-way low frequency electromagnetic communication, and an electronic command unit capable of two way low frequency electromagnetic communication.
Some of the many advantages associated with the communication system of the present invention are as follows.
First is that the system is useful for sending and receiving signals and data to and from devices located within steel 35 containment units such as pipelines or storage tanks. Second, the system can send and receive signals at high rates of speed and over relatively large distances. Third, is that the system can be programmed to operate at different frequencies in order to adapt and take advantage of local conditions offering the least amount of traffic or extraneous interference.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention will now be described in greater detail and will be better understood when read in conjunction with the accompanying drawing, in which:
Figure 1 is a schematic representation of one embodiment of the present invention showing possible positioning of the three communication units;
Figure 2 is an electronic operations block diagram for the present invention.
DETAILED DESCRIPTION
For the purposes of illustration, the present invention is described with reference to use in a pipeline. It will be appreciated, however, that the communications system and the techniques described herein may be adapted for use with any suitable containment vessel such as storage tanks, bins, railway cars, tanker trucks, etc.
Referring to Fig. 1, a pipeline tool 20, is placed inside a pipeline 5 and moved along by the flow of product in the pipeline to a desired location.
A multi-frequency remote communication system includes a control unit 30 located remote from the pipeline 5.
Multi-frequency remote communication system 1 also includes a translator unit 40 located on the outside surface of the pipeline wall 10 near the location of pipeline tool 20 deployed inside pipeline 5. Control unit 30 may be located at a distance of up 2000 meters (6562 feet) from translator unit 40 depending on terrain, and may be hand held. Control unit 30 and translator unit 40 are designed for mutual two-way radio frequency (RF) communication. Multi-frequency remote 3 5 communication system 1 further includes an electronic command unit 50 attached to pipeline tool 20 located inside pipeline 5.
Command unit 50 and translator unit 40 are designed for mutual two-way electromagnetic (EM) communication at low frequency through pipeline wall 10. The working distance between translator unit 40 and command unit 50 can range up to 3.66 meters (12 feet) depending upon the thickness of pipeline wall 10 and the nature of the product within the pipeline 5.
Translator unit 40 also performs two-way translation of RF signals to low frequency EM signals and of low frequency EM
signals and data to RF signals and data.
Electronic command unit 50 controls pipeline tool 20 by responding to commands sent by control unit 30 and translator unit 40.
The operation of one embodiment of the present invention will now be described in detail with reference once again to Figure 1. RF signals 35 are transmitted from control unit 30 to translator unit 40. Translator unit 40 receives RF
signals 35 from control unit 30 and converts them to low frequency EM signals 45. Translator unit 40 transmits low frequency EM signals 45 through pipeline wall 10 to electronic command unit 50 attached to pipeline tool 20 located inside pipeline 5. Electronic command unit 50 receives low frequency EM signals from translator unit 40 for controlling pipeline tool 20 and transmits data 46 received from pipeline tool 20, through the wall of pipeline 10 to translator unit 40 located on the outside of the pipeline wall. EM signals 46 are received by translator unit 40 and converted to RF signals 36 which are transmitted by translator unit 40 to control unit 30. Control unit 30 receives RF signals 36 from translator unit 40.
The penetrating characteristics of EM frequencies are significantly increased as the frequency is lowered, however, at low EM frequencies the ability to carry data at a usable speed is considerably reduced. Frequencies in the range of 22hz have greater penetrating ability when compared to frequencies in the range of 97hz, however, data transmission speed of frequencies in the range of 22Mhz is severely limited.
The frequency of EM signals 45 and 46 transmitted through pipeline wall 10 between translator unit 40 and command unit 50 is programmable within a range between 75hz and 110hz.
At these frequencies, the data handling speed is in the range of 20 to 30 baud, using 8 data bits, 1 start bit and 1 stop bit.
In a preferred embodiment of the present invention the optimum operating frequency has been found to be 97.8hz.
The frequency of RF signals 35 and 36 transmitted between control unit 30 and translator unit 40 is programmable within a range between 450Mhz and 470Mhz. To determine the most advantageous frequency for RF signals 35 and 36, the radio frequency band of the electromagnetic spectrum is monitored and the frequency having the least amount of traffic and providing the least amount of extraneous interference is selected.
An example of the operation of multi-frequency remote communication system 1 will now be described in relation to the operation and control of a pipeline packer or isolation tool (tool) of the kind described in our copending International Application PCT/CA97/00055. Generally, multi-frequency remote communication system 1 is used to send operating instructions to and receive data from the tool. The operating instructions relate to the various amperages, force factorsj and voltages at which it is desired that the tool operate. Once the tool has received an instruction via multi-frequency remote communication system 1 it will request confirmation of the command and will not carry out any action until confirmation has been received and a special code is entered. This process of data transmission and confirmation, back and forth between the tool and control unit 30, takes place for each command sent to the tool. In return, the tool sends data, via multi-frequency remote communication system 1, relating to the remaining battery voltage, which battery pack is in use, amount of amperage each motor is drawing, amount of force being applied to pipeline wall 10 and up and downstream pipeline pressure. This type of data will normally be transmitted by the tool on a continuous basis.
Once the tool reaches programmed force and amperage constants it will automatically shut down. During an operation, or at any time while the tool is holding pipeline pressure, should the force factor fall below the lower programmed limits, the motors will automatically restart and return the tool to the proper force factor. At the same time, the tool will constantly transmit data relating to is current status and function. An emergency halt command can be issued through multi-frequency remote communication system 1 at any time should the operator deem it necessary.
Isolation tools are normally used in pairs to close off a section of an active pipeline to allow replacement of a corroded or damaged section. This saves the time and great expense of shutting down the complete pipeline. Isolation tools have been in use generally for a number of years. However, with the present system, isotools can be instructed to perform tasks and feed back information. The system is remotely controlled using radio and electromagnetic coupling as the communications methods. This also means that the operator need not be close to the pipeline.
System Overview The system is divided into three units shown diagrammatically in Figure 2:
1) Isotool Command Unit 50 2) Base Station Translator 40 3) Hand-held control unit 30 Each isotool has duplicate electromagnetic communi-cations systems and microcontrollers known as the Main and Secondary Unset systems 51 and 52 respectively. The electronics for each are totally separate and there is also a separate battery pack 59 for the Secondary Unset system. This is a back-up system and is only meant to be used to unset the isotool in the event of failure in some part of the Main system. Removal of a failed isotool when in the pipeline locked in position would be a very expensive procedure and would requlre draining of a section of pipeline. During normal operation of the isotool the Secondary Unset system is polled to ensure that it is functioning. Should any problem be detected, the isotool will be taken out of service and flown down the pipeline until it can be removed at a convenient point.
Hand-held control unit 30 uses a radio link to communicate with the translator 40. The translator is used as a signal repeater between the control unit and the isotool command unit 50. Because of the severe attenuation of radio waves through steel piping, electromagnetic coupling is used to send and receive signals from the isotool.
In a typical set-up there will be two isotools, two translators and one or two control units. It is possible to control two isotools with one control unit although this will probably not be done.
1) Isotool Command Unit Usually two isotools are inserted into a pipeline when some repair work is necessary. Each isotool drags a large battery pack behind it which provides all its power. They flow along in the pipeline fluid (whatever it may be) until the faulty section of pipeline is reached. At that time the fluid flow is halted. The exact position of the isotool in the pipeline can be determined by receiving an electromagnetic pulsing signal from the unit allowing exact placement. As mentioned above, the isotool has two independent electronic systems. Each electronics system consists of nine printed circuit boards mounted in a 6.75" diameter module. Connectors carry the power and signals between the boards. A functional description of each board follows below.
In the stack, the boards are arranged in the following order from bottom to top:
1) Main and Secondary Unset Motor Controls.
2) Bypass Motor Controls.
3) Main Microcontroller.
4) Main Electromagnetic Transmitter.
5) Main Electromagnetic Receiver.
_g_ 6) Secondary Unset Microcontroller.
_g_ 6) Secondary Unset Microcontroller.
7) Secondary Unset Electromagnetic Transmitter.
8) Secondary Unset Electromagnetic Receiver.
9) Motor and Secondary Unset Battery Connector Interface.
1) Main and Secondary Unset Motor Control Board This board has the control electronics for two motors 80 and 90 which operate in tandem in a normal functioning tool.
The motors are powered from 24 Volts DC and are used to open (set) or close (unset) a clamp system which holds and seals the isotool in the pipeline while the repair work is being performed. The switches used to control the motors are FETs and require heat sinks. For this reason this board is placed at the bottom of the stack to allow the FETs to be fastened to the baseplate metalwork to afford cooling.
An added complication is that power is supplied to the both motors from one of two main battery packs - Battery 65 and Battery 66. A separate Secondary Unset battery 59 provides power to unset the tool in an emergency should it be necessary.
Twelve FETs are used in two H-bridge configurations on the Main and Secondary Unset Motors 80 and 90. These consist of two battery selection FETs on the high side and one on the low side at either end of each motor. Another two FETs are used on the Secondary Unset Motor (only one motor is used for an emergency unset) to select power from the Secondary Unset battery circuitry. There are fuses on each main battery feed and these are mounted on this printed circuit board.
The Main and Secondary Unset control circuits are completely separate except around the Secondary Unset motor control. As this can be operated by either the Main or Secondary Unset control circuits, FETs from both circuits converge here. Interlock circuitry is used to prevent both control circuits from trying to operate the Secondary Unset motor control at the same time. The Secondary Unset control circuitry has priority.
1) Main and Secondary Unset Motor Control Board This board has the control electronics for two motors 80 and 90 which operate in tandem in a normal functioning tool.
The motors are powered from 24 Volts DC and are used to open (set) or close (unset) a clamp system which holds and seals the isotool in the pipeline while the repair work is being performed. The switches used to control the motors are FETs and require heat sinks. For this reason this board is placed at the bottom of the stack to allow the FETs to be fastened to the baseplate metalwork to afford cooling.
An added complication is that power is supplied to the both motors from one of two main battery packs - Battery 65 and Battery 66. A separate Secondary Unset battery 59 provides power to unset the tool in an emergency should it be necessary.
Twelve FETs are used in two H-bridge configurations on the Main and Secondary Unset Motors 80 and 90. These consist of two battery selection FETs on the high side and one on the low side at either end of each motor. Another two FETs are used on the Secondary Unset Motor (only one motor is used for an emergency unset) to select power from the Secondary Unset battery circuitry. There are fuses on each main battery feed and these are mounted on this printed circuit board.
The Main and Secondary Unset control circuits are completely separate except around the Secondary Unset motor control. As this can be operated by either the Main or Secondary Unset control circuits, FETs from both circuits converge here. Interlock circuitry is used to prevent both control circuits from trying to operate the Secondary Unset motor control at the same time. The Secondary Unset control circuitry has priority.
The current drawn by both motors is monitored for two reasons. Firstly as part of a feedback loop to determine when the motors have stalled or reached a programmed current level.
The control circuitry removes the power from both motors in either of these scenarios. Secondly to detect if there is a short circuit across the motor which produces a hardware trip in the control circuitry. Calibration and offset controls for the motor current monitoring are also on this board.
Also part of the feedback loop is a series of strain gauges 100 to measure how much pressure is being exerted by the isotool sealing clamps on the pipeline wall. A strain gauge trip value can also be programmed to turn off the power to the motors when the desired strain value is reached. Once the tool is set, the programmed strain gauge setting is maintained by activating the set motors if the value falls below the required level.
This ensures that even with any settling of the tool or sealing material the clamp should not become loose or slip inside the pipeline. There could be a serious accident if this happened.
The two motors 80 and 90 are also used for the standard Unset. The motor current sensors determine when the unit is fully unset and removes power from the motors. If a Secondary Unset is being performed, only one motor is used. As mentioned earlier, the Main set/unset control circuitry 51 is disabled when the Secondary Unset is activated. Because there is only one motor operating, it takes a greater time to unset the tool.
However, as the Secondary Unset 52 is a last chance action to release the tool so that it does not jam in the pipeline, this is a small price to pay.
2) By~ass Motor Control Board There are three Bypass Motors in the isotool of this example. These are small motors which control valves. When the valves are opened, pipeline fluid flows through a small diameter tube or tubes from one side of the isotool to the other. The Bypass Motors are opened at the end of a pipeline repair cycle in readiness for the tool Unset. As the section of pipeline that has been replaced is full of air, before releasing the tool the air has to be replaced with pipeline fluid. To determine when the pressure has been equalised there are pressure sensors 110 and 120 mounted in the tool on the upstream and downstream ends thereof. Once the bypass valves are open, the sensor readings are sent back to the control unit 30 at frequent intervals so the operator can monitor progress.
The Bypass Motor control circuitry consists of an H-bridge around each motor. (A total of 12 FETs.) Each motor is individually controlled and its current monitored. The motor only takes a matter of a few seconds to open the bypass valves and completion of the task is detected by an increase in the motor current. Hardware then trips the control circuitry and sets a flag to inform the microcontroller that a particular motor has completed the open or close cycle. As each motor control circuit is separate, it does not matter that one motor may take a little longer than another. Because the motors are low current, the increase in current upon stalling is not too significant. Should the circuitry not detect that a motor has stalled, there is a time-out of 10 seconds after which power is removed from the motor. A signal is sent to the control unit to the effect that one or more of the Bypass Motors have timed out and that there could be a problem in the tool.
Each Bypass Motor control system has independent fuses on the power feed. This means that even if there is a failure in one set of electronics, the other two Bypass Motors will be able to complete the task.
Once the pressure has been equalised on both sides of the isotool, the bypass valves are closed and the tool can be unset. It is then free to flow with the pipeline fluid to the location of the next job.
3) Main Microcontroller Board The main microcontroller board is the heart of the isotool command system. It performs the following functions:
1) Sends the commands to the Set/Unset Motors and the Bypass Valves and monitors the motor currents.
2) Receives data from the strain gauges and the two fluid pressure sensors.
3) Monitors the voltage of both battery packs.
4) Has a watchdog timer to detect problems with the running of the software.
5) Looks after all the communications with the control unit by way of the translator.
Also on the printed circuit boards are:
1) A 5 Volt power supply for all the main system logic circuitry.
2) A real time clock so that commands or information can be time stamped.
3) A hardware sleep timer with programmable jumpers to select sleep intervals.
4) Calibration and offset potentiometers for the pressure sensors.
The microcontroller has two modes of operation; sleep mode and normal mode. Due to the length of time that the isotool may spend in the pipeline travelling between jobs, in order to save battery power, it is advantageous to be able to put the whole tool to sleep.
Sleep mode is entered either by a command from the hand-held control unit or after an extended period of receiving no messages. In this mode, a hardware timer is activated and the power to all other circuitry and boards is shut down. The current drawn in this mode is 2-4mA. Hardware jumpers determine the length of the sleep period up to 35 hours. At the end of the sleep period power is reapplied to the microcontroller.
This then wakes up and turns on the electromagnetic receiver which listens to see if there is a message directed to it.
After a period of time, perhaps 30 seconds or so, if no message has been received, the hardware timer is once again activated and the tool goes back to sleep. Should a message be received, the microcontroller remains awake and sends an acknowledgement.
The tool is then ready to receive commands and begin work. It will remain awake for as long as it is receiving messages from the control unit.
A watchdog timer is incorporated into the microcontroller. If the software stops running, the watchdog will reset the microcontroller to restart it again. Mechanical shock to the tool causing a connector to very briefly lose contact is one possible reason for the software to freeze. If a watchdog reset is detected by the microcontroller, this fact will be sent to the control unit after it has finished rebooting the system so that normal operations can be resumed.
4) Main Electromaqnetic Transmitter Board This card is responsible for modulating, demodulating, and transmitting the modulated signal to the coil 91. The incoming and outgoing modulated signals are transmitted and received by use of a modem. Transmission of the modulated signal is accomplished with two totem-pole drivers. One on each side of the transmit coil 91. These drivers are put in a tristated mode when transmission is not taking place. More information on the EM communications is provided below with reference to Communications Overview.
5) Main Electromaqnetic Receiver Board This is responsible for receiving electromagnetic signals generated by the translator. The received signal is amplified, filtered and then sent to the Main Electromagnetic Transmitter Board. The receive section filters out signals that are not between 85Hz and 110Hz. The demodulation of this signal takes place on the Main Electromagnetic Transmitter Board by the .
modem. This modem with its automatic gain control produces serial data that is sent to the Main Microcontroller. When the microcontroller wakes up from sleep mode, after initialisation it then turns on the Main Electromagnetic Receiver 130 to listen for messages. More information on the EM communications is provided below with reference to Communications Overview.
6) Secondary Unset Microcontroller Board The Secondary Unset Microcontroller Board is identical to the Main Microcontroller Board except that there are no adjustments for sensors on the board. It has its own independent Sleep Mode timer and behaves in the same way as the Main Microcontroller Board. Once awake, the Secondary Unset Microcontroller Board is polled by the control unit periodically.
Under normal operating conditions, the power to operate the Secondary Unset system is drawn from either of the main battery packs. However, should they fail, it will be powered from the Secondary Unset battery. The microcontroller monitors the voltage of this battery. Any logic circuitry related to the 20 -Secondary Unset system is powered by the 5 Volt power supply on this board. The only command that the Secondary Unset Microcontroller Board sends out is to the Main and Secondary Unset Motor Controls Board to initiate a Secondary Unset. This command has priority over the Main Set/Unset circuitry and disables power to it and this is in case there is some hardware or software fault that is trying to activate a set or unset.
As mentioned earlier this is used to release the isotool from the pipeline in the event of failure of the Main electronics system in some way.
7) Secondary Unset Electromaqnetic Transmitter Board This card is responsible for modulating, demodulating, and transmitting the modulated signal to the coil 93. The incoming and outgoing modulated signals are transmitted and received by use of a modem. Transmission of the modulated signal is accomplished with two totem-pole drivers. One on each side of the transmit coil 93. These drivers are put in a tristated mode when transmission is not taking place. Because the main control system and backup system have different ID's, only the system with the proper ID will respond after having received a valid packet. Never will they respond at the same time. For more information on the EM communications read the Communications Overview.
8) Secondary Unset Electromaqnetic Receiver Board This is responsible for receiving electromagnetic signals generated by the translator. The Secondary Unset Electromagnetic Receiver 150 is a second receiver that reads everything that the main receiver card does except it routes the messages to the Secondary Unset Microcontroller. It is up to this microcontroller to determine by the destination ID if the signal is for itself or for the main receiver. It shares the same coupling coil 92 as the Main Receiver Coil 92. The Main and Secondary Unset units have different IDs and so the microcontroller will only respond when the message is meant for it. For more information on the EM communications, reference is made to the Communications Overview below.
9) Motor and Secondary Unset Battery Connector Interface Board At the top of the stack of circuit boards in the module, this board has four connectors. These are interfaces for the following:
1) The three bypass motors.
2) Main and Secondary Unset Motors.
3) Strain Gauge and Downstream Fluid Pressure Sensor Circuitry.
4) Secondary Unset Battery Pack.
Another connector board mounted to the main part of the tool mates up to this board.
2) Translator The translator 40 acts as a repeater between control unit and the isotool. It is equipped with a UHF radio transmitter/receiver 170 and an electromagnetic transmitter /
receiver system 175 all on one printed circuit board. Messages are received from and sent to the control unit 30 on the radio link in the 450-470 Mhz range. A message received from the control unit at 4800 baud is briefly stored in memory and then passed to the Electromagnetic Transmitter at approximately 23 baud. The output of the transmitter is passed to the coil 176 which couples the signal to the coil 92 on the isotool inside the pipeline. Similarly, a response message from the isotool is received by the translator at around 23 baud by the Electromagnetic Receiver and retransmitted to the control unit at 4800 baud on the UHF radio link. The translator is in contact with both the Main and Secondary Unset units in the isotool. Both Main and Secondary Units receive the packets but the unit who's ID matches that of the destination byte of the packet will respond.
The translator can be placed in position above the isotool in the pipeline and used to establish contact with the isotool. As mentioned earlier, to conserve battery power the isotool is in sleep mode during its travel down the pipeline, only waking up for a brief period to determine if there is contact from the translator. To wake up the isotool, the translator would transmit repeatedly an all-call message at an interval which would guarantee that the isotool would get it.
Using the transmitter on the translator for extended periods of time is not a problem as the batteries can be easily replaced.
Sirens and strobe lights can be fitted on the translator to warn of imminent failure of the isotool to hold back the pipeline pressure. The isotool sends a message that it cannot maintain sufficient setting pressure against the pipellne wall and this means that the tool could soon slip. The translator would then activate the warning systems. The message would also be sent to the control unit.
3) Hand-held control unit This is the third part of the system. This allows the operator to send messages to the command unit in the isotool by way of the translator.
- Mounted in a case, the hand-held control unit consists of 1) 450-470 Mhz transmitter/receiver unit.
2) Two 4 line x 20 character LCDs (liquid crystal display) which are backlit.
3) Four LED's to indicate communications status.
4) Microcontroller, real time clock and data logging module.
5) Keypad.
6) 12 Volt, 2.5 Ah Nickel Metal Hydride battery pack with charger circuitry.
7) Connectors for RS-232 and Power/Battery charger.
There are two printed circuit boards in the control unit. The radio board together with the radio power supply, digital interface circuitry and electroluminescent LCD back light power unit is mounted behind the LCD's. The rest of the circuitry is mounted on a PCB (printed circuit board) with the battery pack laying behind the PCB in the lower part of the case. A flexible antenna 55 is mounted from the top edge of the control unit.
Transmission power of the radio is 2 Watts and uses NBFM. This means that communications to the translator over distances exceeding 2 miles could be possible dependent upon the terrain. The default frequency is 464.6375 Mhz which is a dedicated data channel throughout the country, as defined by Industry Canada. However, the radio frequency is programmable to any channel within the 450-470 Mhz range should interference be experienced on this channel. Each Province and Territory also has at least one frequency which can be used specifically for data communications.
When the complete system is in operation, the control unit is in constant communication with the translator. Commands are sent to the translator to be relayed to the isotool command unit and status information from the command unit is sent back to the control unit. The green LED's on the control unit show the quality of the communications link. A steady - on LED means that the communications link is good and that the messages are being received without errors. Should there be some errors in the messages, the LED relevant to that link may go out briefly.
Total operating time with the battery pack can be 14 hrs dependent upon frequency of transmission and usage of the back light. Battery voltage is continuously monitored and when the capacity is down to 10~ reserve, a warning is flashed on the LCD. More urgent warnings appear on the display as the battery capacity is reduced. If charging is not initiated, then the control unit will shut down to protect the operational reliability of the battery.
Charging of the battery is achieved by connecting a cable to a recharge connector on the control unit. Suitable power sources are a car battery via the cigarette lighter or an 8 to 16 volt power supply. Included in the battery charger input circuitry is over-voltage and reverse polarity protection of the battery. Overheating of the battery is protected by a thermal trip in the battery pack. Battery charging is totally automatic and does not affect operation of the control unit.
Once the battery is fully charged, the charger circuitry goes into trickle charge mode thereby maintaining the battery charge at full. During the time that the control unit is connected to an external power source, power is not drawn from the battery pack.
To prevent accidents or keys being pushed unintentionally all command functions from the control unit to the isotool command unit, via the translator, require entry of a four digit supervisor code before the command is sent. Even switching off the control unit requires supervisor code entry.
Access to menus to change trip values or radio frequency used to communicate with the translator also require entry of supervlsor code.
During the Set and Unset Procedures, readings will be received from the isotool relating to Main and Secondary Unset motor currents along with strain gauge values. Readings from the upstream and downstream pressure sensors are also being continuously received. Any commands sent to the isotool will be stored in the data logging module along with the supervisor code and time stamped. The stored data can be downloaded to a lap-top computer through the RS-232 port. If the data logging module becomes full, it will begin to overwrite the existing data.
All the variables as relating to the commands for the isotool command unit are stored in the control unit. Each time the isotool wakes up to begin a project, it is sent the stored values of all the trip functions. These stored values are also sent if the isotool starts up after watchdog reset. The trip values relate to items such as the following:
1) Maximum Set motor current. Exceeding this value causes the logic circuit to cut the power to the motors.
2) Maximum Unset motor current, after an unset is in progress. This is to detect when the tool is fully unset and the motor has stalled.
3) Maximum and delta strain gauge readings for the set motors to maintain the set. The delta value is the fall in strain gauge readings before the' set motor is reapplied.
Csm~-ln;cation~ Overview The isotool's ability to operate hinges on the ability of the command unit to transmit and receive through a 0.5 inch or less pipe wall. Tool transmitters normally operate at a frequency of about 30Hz. Most equipment operates from 120V
60Hz. The higher frequency starts to greatly attenuate at frequencies greater than 120Hz. It is for this reason the communication frequency was chosen at about 97.5Hz as a center frequency. This frequency can be changed depending on the ~ r j~
application. The mark frequency is 106Hz and the space frequency is 89Hz. The UHF link communicates at 4800 baud and operates between 45OMhz to 47OMhz.
UHF E.M.
Handheld ~ ~ Translator ~ ~ Command Unit Controller A packet originates from the handheld controller and is sent by a UHF radio to the translator. The translator then determines if the packet is for itself. If so, it responds to the packet, else it transmits the packet to the isotool. The electro-magnetic transmit section works by sending a serial packet generated by the translator microprocessor's UART and modulating it. The modulated signal is then sent to a dual totempole driver system to switch current into the transmit coil and control the direction of the current in the coil. A
electromagnetic field is produced by current going through the coil. The field produced passes by the receive coil 177 and induces a voltage across the coil. The amount of signal produced is relational to the distance from the transmit coil as well as the strength of the transmit coil. This incoming signal is amplified and filtered so that only frequencies between 85Hz and llOHz will be able to pass through. The aforementioned mark and space frequencies are within this range.
This system can be altered to use different frequencies for different applications. The received signal is demodulated to produce serial data which can then be interpreted by the serial UART internal to the Main and Secondary Unset Microprocessor.
The response packet back follows the same method for modulation detection and UHF response back to the hand-held control unit.
The above described embodiments of the present invention are meant to be illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications, which would be readily apparent to one skilled in the art, are intended to be within the scope of the present invention. The only limitations to the scope of the present invention are set out in the following appended claims.
The control circuitry removes the power from both motors in either of these scenarios. Secondly to detect if there is a short circuit across the motor which produces a hardware trip in the control circuitry. Calibration and offset controls for the motor current monitoring are also on this board.
Also part of the feedback loop is a series of strain gauges 100 to measure how much pressure is being exerted by the isotool sealing clamps on the pipeline wall. A strain gauge trip value can also be programmed to turn off the power to the motors when the desired strain value is reached. Once the tool is set, the programmed strain gauge setting is maintained by activating the set motors if the value falls below the required level.
This ensures that even with any settling of the tool or sealing material the clamp should not become loose or slip inside the pipeline. There could be a serious accident if this happened.
The two motors 80 and 90 are also used for the standard Unset. The motor current sensors determine when the unit is fully unset and removes power from the motors. If a Secondary Unset is being performed, only one motor is used. As mentioned earlier, the Main set/unset control circuitry 51 is disabled when the Secondary Unset is activated. Because there is only one motor operating, it takes a greater time to unset the tool.
However, as the Secondary Unset 52 is a last chance action to release the tool so that it does not jam in the pipeline, this is a small price to pay.
2) By~ass Motor Control Board There are three Bypass Motors in the isotool of this example. These are small motors which control valves. When the valves are opened, pipeline fluid flows through a small diameter tube or tubes from one side of the isotool to the other. The Bypass Motors are opened at the end of a pipeline repair cycle in readiness for the tool Unset. As the section of pipeline that has been replaced is full of air, before releasing the tool the air has to be replaced with pipeline fluid. To determine when the pressure has been equalised there are pressure sensors 110 and 120 mounted in the tool on the upstream and downstream ends thereof. Once the bypass valves are open, the sensor readings are sent back to the control unit 30 at frequent intervals so the operator can monitor progress.
The Bypass Motor control circuitry consists of an H-bridge around each motor. (A total of 12 FETs.) Each motor is individually controlled and its current monitored. The motor only takes a matter of a few seconds to open the bypass valves and completion of the task is detected by an increase in the motor current. Hardware then trips the control circuitry and sets a flag to inform the microcontroller that a particular motor has completed the open or close cycle. As each motor control circuit is separate, it does not matter that one motor may take a little longer than another. Because the motors are low current, the increase in current upon stalling is not too significant. Should the circuitry not detect that a motor has stalled, there is a time-out of 10 seconds after which power is removed from the motor. A signal is sent to the control unit to the effect that one or more of the Bypass Motors have timed out and that there could be a problem in the tool.
Each Bypass Motor control system has independent fuses on the power feed. This means that even if there is a failure in one set of electronics, the other two Bypass Motors will be able to complete the task.
Once the pressure has been equalised on both sides of the isotool, the bypass valves are closed and the tool can be unset. It is then free to flow with the pipeline fluid to the location of the next job.
3) Main Microcontroller Board The main microcontroller board is the heart of the isotool command system. It performs the following functions:
1) Sends the commands to the Set/Unset Motors and the Bypass Valves and monitors the motor currents.
2) Receives data from the strain gauges and the two fluid pressure sensors.
3) Monitors the voltage of both battery packs.
4) Has a watchdog timer to detect problems with the running of the software.
5) Looks after all the communications with the control unit by way of the translator.
Also on the printed circuit boards are:
1) A 5 Volt power supply for all the main system logic circuitry.
2) A real time clock so that commands or information can be time stamped.
3) A hardware sleep timer with programmable jumpers to select sleep intervals.
4) Calibration and offset potentiometers for the pressure sensors.
The microcontroller has two modes of operation; sleep mode and normal mode. Due to the length of time that the isotool may spend in the pipeline travelling between jobs, in order to save battery power, it is advantageous to be able to put the whole tool to sleep.
Sleep mode is entered either by a command from the hand-held control unit or after an extended period of receiving no messages. In this mode, a hardware timer is activated and the power to all other circuitry and boards is shut down. The current drawn in this mode is 2-4mA. Hardware jumpers determine the length of the sleep period up to 35 hours. At the end of the sleep period power is reapplied to the microcontroller.
This then wakes up and turns on the electromagnetic receiver which listens to see if there is a message directed to it.
After a period of time, perhaps 30 seconds or so, if no message has been received, the hardware timer is once again activated and the tool goes back to sleep. Should a message be received, the microcontroller remains awake and sends an acknowledgement.
The tool is then ready to receive commands and begin work. It will remain awake for as long as it is receiving messages from the control unit.
A watchdog timer is incorporated into the microcontroller. If the software stops running, the watchdog will reset the microcontroller to restart it again. Mechanical shock to the tool causing a connector to very briefly lose contact is one possible reason for the software to freeze. If a watchdog reset is detected by the microcontroller, this fact will be sent to the control unit after it has finished rebooting the system so that normal operations can be resumed.
4) Main Electromaqnetic Transmitter Board This card is responsible for modulating, demodulating, and transmitting the modulated signal to the coil 91. The incoming and outgoing modulated signals are transmitted and received by use of a modem. Transmission of the modulated signal is accomplished with two totem-pole drivers. One on each side of the transmit coil 91. These drivers are put in a tristated mode when transmission is not taking place. More information on the EM communications is provided below with reference to Communications Overview.
5) Main Electromaqnetic Receiver Board This is responsible for receiving electromagnetic signals generated by the translator. The received signal is amplified, filtered and then sent to the Main Electromagnetic Transmitter Board. The receive section filters out signals that are not between 85Hz and 110Hz. The demodulation of this signal takes place on the Main Electromagnetic Transmitter Board by the .
modem. This modem with its automatic gain control produces serial data that is sent to the Main Microcontroller. When the microcontroller wakes up from sleep mode, after initialisation it then turns on the Main Electromagnetic Receiver 130 to listen for messages. More information on the EM communications is provided below with reference to Communications Overview.
6) Secondary Unset Microcontroller Board The Secondary Unset Microcontroller Board is identical to the Main Microcontroller Board except that there are no adjustments for sensors on the board. It has its own independent Sleep Mode timer and behaves in the same way as the Main Microcontroller Board. Once awake, the Secondary Unset Microcontroller Board is polled by the control unit periodically.
Under normal operating conditions, the power to operate the Secondary Unset system is drawn from either of the main battery packs. However, should they fail, it will be powered from the Secondary Unset battery. The microcontroller monitors the voltage of this battery. Any logic circuitry related to the 20 -Secondary Unset system is powered by the 5 Volt power supply on this board. The only command that the Secondary Unset Microcontroller Board sends out is to the Main and Secondary Unset Motor Controls Board to initiate a Secondary Unset. This command has priority over the Main Set/Unset circuitry and disables power to it and this is in case there is some hardware or software fault that is trying to activate a set or unset.
As mentioned earlier this is used to release the isotool from the pipeline in the event of failure of the Main electronics system in some way.
7) Secondary Unset Electromaqnetic Transmitter Board This card is responsible for modulating, demodulating, and transmitting the modulated signal to the coil 93. The incoming and outgoing modulated signals are transmitted and received by use of a modem. Transmission of the modulated signal is accomplished with two totem-pole drivers. One on each side of the transmit coil 93. These drivers are put in a tristated mode when transmission is not taking place. Because the main control system and backup system have different ID's, only the system with the proper ID will respond after having received a valid packet. Never will they respond at the same time. For more information on the EM communications read the Communications Overview.
8) Secondary Unset Electromaqnetic Receiver Board This is responsible for receiving electromagnetic signals generated by the translator. The Secondary Unset Electromagnetic Receiver 150 is a second receiver that reads everything that the main receiver card does except it routes the messages to the Secondary Unset Microcontroller. It is up to this microcontroller to determine by the destination ID if the signal is for itself or for the main receiver. It shares the same coupling coil 92 as the Main Receiver Coil 92. The Main and Secondary Unset units have different IDs and so the microcontroller will only respond when the message is meant for it. For more information on the EM communications, reference is made to the Communications Overview below.
9) Motor and Secondary Unset Battery Connector Interface Board At the top of the stack of circuit boards in the module, this board has four connectors. These are interfaces for the following:
1) The three bypass motors.
2) Main and Secondary Unset Motors.
3) Strain Gauge and Downstream Fluid Pressure Sensor Circuitry.
4) Secondary Unset Battery Pack.
Another connector board mounted to the main part of the tool mates up to this board.
2) Translator The translator 40 acts as a repeater between control unit and the isotool. It is equipped with a UHF radio transmitter/receiver 170 and an electromagnetic transmitter /
receiver system 175 all on one printed circuit board. Messages are received from and sent to the control unit 30 on the radio link in the 450-470 Mhz range. A message received from the control unit at 4800 baud is briefly stored in memory and then passed to the Electromagnetic Transmitter at approximately 23 baud. The output of the transmitter is passed to the coil 176 which couples the signal to the coil 92 on the isotool inside the pipeline. Similarly, a response message from the isotool is received by the translator at around 23 baud by the Electromagnetic Receiver and retransmitted to the control unit at 4800 baud on the UHF radio link. The translator is in contact with both the Main and Secondary Unset units in the isotool. Both Main and Secondary Units receive the packets but the unit who's ID matches that of the destination byte of the packet will respond.
The translator can be placed in position above the isotool in the pipeline and used to establish contact with the isotool. As mentioned earlier, to conserve battery power the isotool is in sleep mode during its travel down the pipeline, only waking up for a brief period to determine if there is contact from the translator. To wake up the isotool, the translator would transmit repeatedly an all-call message at an interval which would guarantee that the isotool would get it.
Using the transmitter on the translator for extended periods of time is not a problem as the batteries can be easily replaced.
Sirens and strobe lights can be fitted on the translator to warn of imminent failure of the isotool to hold back the pipeline pressure. The isotool sends a message that it cannot maintain sufficient setting pressure against the pipellne wall and this means that the tool could soon slip. The translator would then activate the warning systems. The message would also be sent to the control unit.
3) Hand-held control unit This is the third part of the system. This allows the operator to send messages to the command unit in the isotool by way of the translator.
- Mounted in a case, the hand-held control unit consists of 1) 450-470 Mhz transmitter/receiver unit.
2) Two 4 line x 20 character LCDs (liquid crystal display) which are backlit.
3) Four LED's to indicate communications status.
4) Microcontroller, real time clock and data logging module.
5) Keypad.
6) 12 Volt, 2.5 Ah Nickel Metal Hydride battery pack with charger circuitry.
7) Connectors for RS-232 and Power/Battery charger.
There are two printed circuit boards in the control unit. The radio board together with the radio power supply, digital interface circuitry and electroluminescent LCD back light power unit is mounted behind the LCD's. The rest of the circuitry is mounted on a PCB (printed circuit board) with the battery pack laying behind the PCB in the lower part of the case. A flexible antenna 55 is mounted from the top edge of the control unit.
Transmission power of the radio is 2 Watts and uses NBFM. This means that communications to the translator over distances exceeding 2 miles could be possible dependent upon the terrain. The default frequency is 464.6375 Mhz which is a dedicated data channel throughout the country, as defined by Industry Canada. However, the radio frequency is programmable to any channel within the 450-470 Mhz range should interference be experienced on this channel. Each Province and Territory also has at least one frequency which can be used specifically for data communications.
When the complete system is in operation, the control unit is in constant communication with the translator. Commands are sent to the translator to be relayed to the isotool command unit and status information from the command unit is sent back to the control unit. The green LED's on the control unit show the quality of the communications link. A steady - on LED means that the communications link is good and that the messages are being received without errors. Should there be some errors in the messages, the LED relevant to that link may go out briefly.
Total operating time with the battery pack can be 14 hrs dependent upon frequency of transmission and usage of the back light. Battery voltage is continuously monitored and when the capacity is down to 10~ reserve, a warning is flashed on the LCD. More urgent warnings appear on the display as the battery capacity is reduced. If charging is not initiated, then the control unit will shut down to protect the operational reliability of the battery.
Charging of the battery is achieved by connecting a cable to a recharge connector on the control unit. Suitable power sources are a car battery via the cigarette lighter or an 8 to 16 volt power supply. Included in the battery charger input circuitry is over-voltage and reverse polarity protection of the battery. Overheating of the battery is protected by a thermal trip in the battery pack. Battery charging is totally automatic and does not affect operation of the control unit.
Once the battery is fully charged, the charger circuitry goes into trickle charge mode thereby maintaining the battery charge at full. During the time that the control unit is connected to an external power source, power is not drawn from the battery pack.
To prevent accidents or keys being pushed unintentionally all command functions from the control unit to the isotool command unit, via the translator, require entry of a four digit supervisor code before the command is sent. Even switching off the control unit requires supervisor code entry.
Access to menus to change trip values or radio frequency used to communicate with the translator also require entry of supervlsor code.
During the Set and Unset Procedures, readings will be received from the isotool relating to Main and Secondary Unset motor currents along with strain gauge values. Readings from the upstream and downstream pressure sensors are also being continuously received. Any commands sent to the isotool will be stored in the data logging module along with the supervisor code and time stamped. The stored data can be downloaded to a lap-top computer through the RS-232 port. If the data logging module becomes full, it will begin to overwrite the existing data.
All the variables as relating to the commands for the isotool command unit are stored in the control unit. Each time the isotool wakes up to begin a project, it is sent the stored values of all the trip functions. These stored values are also sent if the isotool starts up after watchdog reset. The trip values relate to items such as the following:
1) Maximum Set motor current. Exceeding this value causes the logic circuit to cut the power to the motors.
2) Maximum Unset motor current, after an unset is in progress. This is to detect when the tool is fully unset and the motor has stalled.
3) Maximum and delta strain gauge readings for the set motors to maintain the set. The delta value is the fall in strain gauge readings before the' set motor is reapplied.
Csm~-ln;cation~ Overview The isotool's ability to operate hinges on the ability of the command unit to transmit and receive through a 0.5 inch or less pipe wall. Tool transmitters normally operate at a frequency of about 30Hz. Most equipment operates from 120V
60Hz. The higher frequency starts to greatly attenuate at frequencies greater than 120Hz. It is for this reason the communication frequency was chosen at about 97.5Hz as a center frequency. This frequency can be changed depending on the ~ r j~
application. The mark frequency is 106Hz and the space frequency is 89Hz. The UHF link communicates at 4800 baud and operates between 45OMhz to 47OMhz.
UHF E.M.
Handheld ~ ~ Translator ~ ~ Command Unit Controller A packet originates from the handheld controller and is sent by a UHF radio to the translator. The translator then determines if the packet is for itself. If so, it responds to the packet, else it transmits the packet to the isotool. The electro-magnetic transmit section works by sending a serial packet generated by the translator microprocessor's UART and modulating it. The modulated signal is then sent to a dual totempole driver system to switch current into the transmit coil and control the direction of the current in the coil. A
electromagnetic field is produced by current going through the coil. The field produced passes by the receive coil 177 and induces a voltage across the coil. The amount of signal produced is relational to the distance from the transmit coil as well as the strength of the transmit coil. This incoming signal is amplified and filtered so that only frequencies between 85Hz and llOHz will be able to pass through. The aforementioned mark and space frequencies are within this range.
This system can be altered to use different frequencies for different applications. The received signal is demodulated to produce serial data which can then be interpreted by the serial UART internal to the Main and Secondary Unset Microprocessor.
The response packet back follows the same method for modulation detection and UHF response back to the hand-held control unit.
The above described embodiments of the present invention are meant to be illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications, which would be readily apparent to one skilled in the art, are intended to be within the scope of the present invention. The only limitations to the scope of the present invention are set out in the following appended claims.
Claims (8)
1. A multi-frequency remote communication system comprising:
a control unit capable of two-way radio frequency communication;
a translator unit capable of both two-way radio frequency communication and two-way low frequency electromagnetic communication; and an electronic command unit capable of two way low frequency electromagnetic communication.
a control unit capable of two-way radio frequency communication;
a translator unit capable of both two-way radio frequency communication and two-way low frequency electromagnetic communication; and an electronic command unit capable of two way low frequency electromagnetic communication.
2. A communication system according to claim 1, wherein the radio frequency at which said control unit and said translator unit operate is selectable within a range.
3. A communication system according to claim 2, wherein said range within which said radio frequency is selectable is between 450Mhz and 470Mhz.
4. A communication system according to claim 1, 2 or 3 wherein the electromagnetic frequency at which said translator unit and said command unit operate is selectable within a range.
5. A communication system according to claim 4 wherein the range within which said electromagnetic frequency is selectable is between 75Mhz and 110Mhz.
6. A communication system according to claim 4 wherein said translator unit and said command unit operate at an electromagnetic frequency of 98.7Mhz.
7. A communication system according to claim 1, wherein said electronic command unit is located inside a containment vessel, said translator unit is located outside said containment vessel and said control unit is located remote from said translator unit and said command unit.
8. A communication system according to claim 7, wherein said containment vessel is made of metal.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002220480A CA2220480A1 (en) | 1997-11-07 | 1997-11-07 | Multi-frequency remote communications system |
| IDP981453A ID22201A (en) | 1997-11-07 | 1998-11-05 | MANAGEMENT SYSTEM AND METHOD OF COMMUNICATION, COMMANDING AND CONTROLLING OF MOST REMOTE LOCATIONS |
| PCT/CA1998/001030 WO1999025070A2 (en) | 1997-11-07 | 1998-11-06 | Multi-frequency remote location, communication, command and control system and method |
| AU10166/99A AU1016699A (en) | 1997-11-07 | 1998-11-06 | Multi-frequency remote location, communication, command and control system and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002220480A CA2220480A1 (en) | 1997-11-07 | 1997-11-07 | Multi-frequency remote communications system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2220480A1 true CA2220480A1 (en) | 1999-05-07 |
Family
ID=4161735
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002220480A Abandoned CA2220480A1 (en) | 1997-11-07 | 1997-11-07 | Multi-frequency remote communications system |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU1016699A (en) |
| CA (1) | CA2220480A1 (en) |
| ID (1) | ID22201A (en) |
| WO (1) | WO1999025070A2 (en) |
Families Citing this family (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101204020A (en) | 2005-06-23 | 2008-06-18 | 皇家飞利浦电子股份有限公司 | An inductive communication system with increased noise immunity using a low-complexity transmitter |
| NO334629B1 (en) | 2009-04-17 | 2014-04-28 | Tdw Offshore Services As | System and device for monitoring a movable plug element in a pipeline |
| EP2352002B1 (en) * | 2010-01-29 | 2013-10-30 | Politecnico Di Torino | A system for remote leak detection and/or path tracking for underground fluid transportation pipelines |
| US9435190B2 (en) | 2010-08-05 | 2016-09-06 | Fmc Technologies, Inc. | Wireless communication system for monitoring of subsea well casing annuli |
| GB2485782A (en) * | 2010-09-20 | 2012-05-30 | Wfs Technologies Ltd | Low frequency electromagnetic signals are passed through a barrier comprising electrically conductive and electrically insulative layers |
| US8474533B2 (en) | 2010-12-07 | 2013-07-02 | Halliburton Energy Services, Inc. | Gas generator for pressurizing downhole samples |
| GB2486685A (en) | 2010-12-20 | 2012-06-27 | Expro North Sea Ltd | Electrical power and/or signal transmission through a metallic wall |
| US9169705B2 (en) | 2012-10-25 | 2015-10-27 | Halliburton Energy Services, Inc. | Pressure relief-assisted packer |
| US20150355045A1 (en) * | 2013-01-28 | 2015-12-10 | Aquarius Spectrum Ltd. | Method and apparatus for detecting leaks in a pipeline network |
| US9587486B2 (en) | 2013-02-28 | 2017-03-07 | Halliburton Energy Services, Inc. | Method and apparatus for magnetic pulse signature actuation |
| US9726009B2 (en) | 2013-03-12 | 2017-08-08 | Halliburton Energy Services, Inc. | Wellbore servicing tools, systems and methods utilizing near-field communication |
| US9284817B2 (en) | 2013-03-14 | 2016-03-15 | Halliburton Energy Services, Inc. | Dual magnetic sensor actuation assembly |
| US9172406B2 (en) | 2013-05-03 | 2015-10-27 | Control Devices, Inc. | Pressure resistant housing device for protecting an electromagnetic transmitter |
| US9752414B2 (en) | 2013-05-31 | 2017-09-05 | Halliburton Energy Services, Inc. | Wellbore servicing tools, systems and methods utilizing downhole wireless switches |
| US20150075770A1 (en) | 2013-05-31 | 2015-03-19 | Michael Linley Fripp | Wireless activation of wellbore tools |
| US9535039B2 (en) | 2014-04-30 | 2017-01-03 | Control Devices, Inc. | Acoustic transmitter and method for underwater pipeline inspection gauges |
| WO2016085465A1 (en) | 2014-11-25 | 2016-06-02 | Halliburton Energy Services, Inc. | Wireless activation of wellbore tools |
| CN105071868B (en) * | 2015-08-05 | 2018-06-01 | 中国华能集团清洁能源技术研究院有限公司 | Signal transmission system |
| US10030961B2 (en) | 2015-11-27 | 2018-07-24 | General Electric Company | Gap measuring device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA55A (en) | 1869-09-15 | N.S. Card | A fruit drier | |
| US5030948A (en) * | 1988-09-19 | 1991-07-09 | Rush Charles T | Multiple characteristic sensitive addressing schema for a multiple receiver data processing network |
| GB2297666B (en) * | 1995-01-31 | 1999-06-02 | British Gas Plc | Signalling to or from a vehicle inside a pipeline |
-
1997
- 1997-11-07 CA CA002220480A patent/CA2220480A1/en not_active Abandoned
-
1998
- 1998-11-05 ID IDP981453A patent/ID22201A/en unknown
- 1998-11-06 AU AU10166/99A patent/AU1016699A/en not_active Abandoned
- 1998-11-06 WO PCT/CA1998/001030 patent/WO1999025070A2/en active Application Filing
Also Published As
| Publication number | Publication date |
|---|---|
| ID22201A (en) | 1999-09-16 |
| WO1999025070A2 (en) | 1999-05-20 |
| WO1999025070A3 (en) | 1999-07-15 |
| AU1016699A (en) | 1999-05-31 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Discontinued |