RU87418U1 - CABLE COMBINED LINK BETWEEN THE MODULES OF THE MONITORING, MANAGEMENT AND SAFETY SYSTEM OF THE LOAD CRANE - Google Patents

Abstract

1. A combined cable communication line between the modules of the monitoring, control and safety system of a crane, including a two-wire data exchange line and a two-wire power supply line, characterized in that it is equipped with at least one galvanic isolation unit, including a digital isolator, built-in into a data exchange line, and an isolating converter of DC voltage to DC voltage, built into the power supply line, with separate power supply for parts of the digital circuit insulator from isolated power sources of the specified isolation transformer. ! 2. The communication line according to claim 1, characterized in that it is made with two galvanic isolation blocks spaced along its length, with a series connection in the power line of the isolating converters of these blocks. ! 3. The communication line according to claims 1 and 2, characterized in that the galvanic isolation unit is made in the form of an adapter with a detachable connection to the communication line.

Description

The utility model relates to electrical communications technology and can be used in monitoring, control and safety systems of hoisting cranes.

Cable combined communication lines are known between modules for monitoring, control and safety systems of hoisting cranes, including a two-wire data exchange line and a two-wire power line for measuring modules of the indicated system from an information-control module (see, for example, RF patent for utility model No. 38747, B66C 23 / 90, 04/05/2004). Such a communication line was used, in particular, in the safety devices of hoisting cranes "Load Limiter ONK-160", manufactured by the Arzamas Electromechanical Plant, for communication of the information-control unit (information display unit "BOI" in the safety devices ONK-160B and ONK-160S or the control unit "BU" in the safety device ONK-160M) and a set of sensors for crane parameters, including analog, digital and discrete sensors, while digital sensors are connected directly to the communication line, and analog sensors through controllers. The communication line provides power to the sensors of the crane parameters from the power supply unit of the load limiter and the exchange of information between the sensors and the information and control unit during operation of the crane, but it has insufficient noise immunity from power lines, lightning discharges and other atmospheric phenomena, as well as when working in conditions of industrial facilities: in the immediate vicinity of powerful engines, welding units, switching equipment, electric melting furnaces or other sources in strong electromagnetic radiation. In such an environment, there is a very high probability of data loss or errors during the transmission of information, followed by shutdown by safety devices of expensive equipment, which increases the cost of downtime, and in some cases is completely unacceptable, for example, in metallurgical production. The noise immunity of the system also reduces the use of cables with the traditional method of shielding them - braiding, since the braid does not have satisfactory shielding capabilities in a wide frequency range and generally does not shield the wires from the magnetic field. In addition, one of the most serious problems that arise when transferring data between electronic devices is the mismatch of the zero potentials of these devices, the so-called “lands”. If you directly connect the earth circuits of different devices using a wire or cable shield, then parasitic circuits arise along which earth currents begin to pass. They cause signal distortion, interference and an increased level of radiation, and with a large difference in ground potentials can lead to damage to devices.

The problem to which the claimed utility model is directed is to create a wired communication line between the modules of the monitoring, control and safety system of the crane, which has increased reliability of data transmission between the modules of this system by increasing the noise immunity from external electromagnetic interference. Additional tasks to be solved and advantages of the claimed utility model will be clear from the following description.

The stated technical problems are solved in that the cable combined communication line between the modules of the monitoring, control and safety system of the crane, including a two-wire data exchange line and a two-wire power line, according to a utility model, is equipped with at least one galvanic isolation unit, including a digital isolator integrated in the data line and an isolating converter of DC voltage to DC voltage integrated in the power line Ia, with the separate power digital isolator circuit parts from isolated power supplies of said insulating converter.

The communication line can be made with two galvanic isolation blocks spaced along its length, with a series connection in the power line of the isolating converters of these blocks.

Preferably, the galvanic isolation unit is made in the form of an adapter with a detachable connection to the communication line.

The proposed combined cable communication line between the modules of the crane monitoring, control and safety system is based on active methods of protection against electromagnetic interference, based on the use of galvanic isolation both in the two-way data exchange line between the modules of this system and in the power line of one of the modules of this systems from another module of the system associated with it, with separate power supply to parts of the digital isolator circuit from isolated power sources of the converter.

The implementation of the communication line with two galvanic isolation blocks spaced apart along its length, with a series connection of the insulating converters of these blocks in the power supply line, allows galvanic isolation blocks to be located in close proximity to the crane monitoring, control and safety system modules, which protects the communication line and modules from lightning and static discharges, increases the noise immunity of modules from electromagnetic interference on long lines communication and significantly reduces the proportion of electromagnetic interference in the signal fed through the cable line, since the signal is normalized by the level at the output of the digital insulator, therefore this design of the cable combined communication line is preferable when used on tower cranes, where the length of the communication line is 100 m or more , or on cranes with an increased length of communication lines.

The implementation of the galvanic isolation unit in the form of an adapter with a plug-in connection to the communication line provides the opportunity to increase the noise immunity of the monitoring, control and safety systems of cranes in operation without replacing the units and modules that make up these systems, while maintaining their standard connecting cables.

The technical result from the use of this utility model is to increase the noise immunity of the communication line from external electromagnetic interference and to protect the system equipment from atmospheric and static electricity discharges.

Figure 1 shows a functional diagram of a control system, control and safety of a crane; figure 2 - the proposed cable combined communication line between the modules of this system; figure 3 is a communication line according to the second embodiment of the utility model.

The monitoring, control and safety system of the crane consists of various components made in the form of electronic devices that measure the parameters of the crane, process information and control actuators. So, for example, the control, control and safety system of the crane shown in FIG. 1 contains an information-control unit 1 and a set of 2 sensors for crane parameters connected to each other via a communication line in the form of a serial interface bus 3. The complex of 2 sensors for crane parameters includes analog, digital and discrete sensors. Digital sensors are connected directly to bus 3 of the serial interface, and analog sensors are connected via controllers (not shown in the drawing). The serial interface bus 3 is a four-wire cable 4, containing a twisted pair of wires of the data exchange line 5, and additionally two wires of the power supply line of the crane parameter sensors from the power supply unit, which is part of the information-control unit 1 (not shown in the drawing). All wires are placed on a common screen. The cable has electrical plug connectors 7 at the ends.

According to the first embodiment of the utility model shown in FIG. 2, the communication line is equipped with one galvanic isolation unit 8, including a digital isolator 9, integrated in the data exchange line 5, and an isolation converter 10 of the DC voltage to the DC voltage (isolation DC / DC converter) built into power supply line 6. In figure 2, the insulation is shown in conditionally parallel lines.

The galvanic isolation unit 8 is made in the form of an adapter equipped with an additional adapter cable 11 for connecting this unit to a set of sensors of the crane parameters.

The adapter contains a housing in which a board is mounted on which the elements of the digital insulator 9 and the isolation converter 10 are mounted, and two electrical plug-in connectors 12 of the “socket” type are mounted on the housing.

The adapter cable 11 is made similar to cable 4 and is equipped at the ends with electrical plug connectors 13 of the “plug” type, similar to connectors 7 at the ends of cable 4. One of the ends of cable 4 is connected to the information-control unit 1, and the other end of cable 4 is connected to complex 2 sensors of parameters of the crane through block 8 galvanic isolation and adapter cable 11.

The isolating converter 10 of the DC voltage to DC voltage can be implemented, for example, on two DCP 021212U microcircuits from Burr Brown. This isolation converter comprises a pulse converter, a transformer and a rectifier.

Digital insulators are currently available in various types: optical, transformer (inductive), capacitive. For this utility model, capacitive digital insulators are most preferable, since they provide higher resistance to magnetic fields, which in production conditions create the main and most powerful interference with the operation of electronic equipment, including the safety equipment of hoisting machines. In addition, they consume about 60% less electricity than high-speed optocouplers and have a higher speed. Such isolators are known and produced by major manufacturers of radio components such as Texas Instruments, Analog Devices, and others. For example, to implement digital isolator 9, Texas Instruments IS0721 and IS0721M microchips can be used with separate power supply to parts of the digital isolator 9 circuit from isolated converter power supplies 10 using power buses 14 and 15.

When the information-control unit 1 is turned on, the supply voltage is supplied through two wires of the power supply line 6 to the input of the isolation transformer 10 and, in addition, is supplied via the power bus 14 to the active elements of the circuit part of the digital insulator 9 connected to its inputs / outputs via two other wires of the line 5 data transmission to the respective outputs / inputs of the information-control unit 1. Constant voltage of the power supply unit of the information-control unit 1 by a pulse converter of an isolating converter chip The applicator 10 is converted into an alternating voltage of high frequency, which is supplied to the primary winding of the transformer of the microcircuit. The pulses from the generator pass through the transformer to the secondary winding, from which they are fed to the rectifier of the isolating converter 10 microcircuit and converted to constant voltage, from which not only the isolated part of the converter microcircuit 10 can be powered, but also external circuits. This constant voltage, on the one hand, is supplied through the adapter cable 11 to the crane parameter sensors to power the electronic part of these sensors and / or other units, and, on the other hand, this voltage is supplied via the power bus 15 to the active elements of the circuit part of the digital insulator 9 connected by its inputs / outputs through two other wires of the data transmission line 5 to the corresponding outputs / inputs of the complex of 2 sensors of the crane parameters or to other external units. Thus, a complete galvanic isolation of the information-control unit 1 from the sensors and / or other external units is ensured, both in power supply and in information and control circuits.

Power to both insulated parts of the digital insulator 9 can be supplied either directly from the input and output of the isolating converter 10, as described above, or through additional intermediate DC / DC converters if the supply voltage of the digital insulator 9 is different from the supply voltage of the sensors or external blocks.

Information and control signals that the information and control unit 1 exchanges with sensors and / or other external units in modern monitoring, control and safety systems of cranes are transmitted, as a rule, in digital form in accordance with the serial interface selected for this system. The control signals are received through two signal wires of the data exchange line 5 from the information-control unit 1 to the inputs of the digital isolator 9 of the galvanic isolation unit 8. In the microcircuit of a digital isolator, the input logical drops are encoded by pulses of one to several nanosecond duration, for example, each positive difference causes two pulses to appear, and each negative one causes one. These pulses are fed to the primary winding of the transformer of the digital isolator chip. The pulses from the secondary winding are fed to a decoding circuit, which restores the input signal. In addition, a special regeneration circuit checks whether the output level of the signal matches the input level even in the absence of logical differences at the input. This is required when the power is turned on, as well as at low data transfer rates or when there is a long absence of a change in the signal level at the input of the device under the influence of interference. The regeneration circuit also protects the secondary circuit from possible voltage surges in the primary circuit, for example, from atmospheric electricity discharges, etc. The signal restored to the original serial code and normalized by level is then transmitted via two signal wires of the adapter cable 11 to the signal inputs of sensors and / or other external blocks.

Similarly, through the same signal wires of the data exchange line 5 and the same circuits of the digital isolator 9, information signals are transmitted in the opposite direction from the crane parameter sensors to the input of the information-control unit 1.

According to the second example of implementation of the utility model shown in Fig. 3, the communication line is equipped with an additional galvanic isolation unit 16, similar to block 8, with the insulating converters 10 of these blocks connected in series to the power line. The additional galvanic isolation unit 16 is equipped with two electrical plug-in connectors 17 of the “socket” type, similar to the connectors 12, and an additional adapter cable 18 with electrical plug-in connectors 19 at the ends of the “plug” type, similar to the connectors 7 and 13. One of the ends of the additional adapter cable 18 connected to the information-control unit 1, and the other end to the input of the additional unit 16 galvanic isolation, the output of which through cable 4 is connected to the input of block 8 galvanic isolation, the output of which is connected to a set of 2 sensors for crane parameters using an adapter cable 11. When using such a communication line, for example, on tower cranes, galvanic isolation units 8 and 16 are located in close proximity to a complex of 2 sensors for crane parameters and the information-control unit 1 With this serial connection of galvanic isolation blocks, protection is provided for a long connecting cable (80-150 m), blocks and sensors located in the lower part of the crane, and information directs the block, located in the cab of the tower crane at a height of 80-130 meters from the possible discharge of atmospheric and static electricity, which often derive Equipment system malfunction or even destroy it.

The claimed device can be manufactured industrially at an instrument-making plant using well-known electronic components and technologies.

Claims (3)

1. A combined cable communication line between the modules of the monitoring, control and safety system of a crane, including a two-wire data exchange line and a two-wire power supply line, characterized in that it is equipped with at least one galvanic isolation unit, including a digital isolator, built-in into a data exchange line, and an isolating converter of DC voltage to DC voltage, built into the power supply line, with separate power supply for parts of the digital circuit insulator from isolated power sources of the specified isolation transformer. 2. The communication line according to claim 1, characterized in that it is made with two galvanic isolation blocks spaced along its length, with a series connection in the power line of the isolating converters of these blocks. 3. The communication line according to claims 1 and 2, characterized in that the galvanic isolation unit is made in the form of an adapter with a detachable connection to the communication line.