JPS60243721A - Plug-in unit system - Google Patents

Abstract

PURPOSE:To prevent data from misoutput and a system from stop and to improve reliability by delaying a reset signal for a fixed period at the start of maintenance of a hot-line. CONSTITUTION:A digital input unit 5 is constituted of a maintenance connector 11, an interruption generating circuit 12, an input data connector 13, a digital input circuit 14, and a data bus driver 17 and a delay circuit 20 is also added to the unit 5. The unit 5 is connected to a system bus through an interruption signal line 15 and a data bus 16 and the hot-line maintenance and inspection of the unit 5 are executed by fitting a sub-connector 10 from the external. The added delay circuit 20 generates a reset signal RS with the delay of a fixed period from the input of a maintenance signal MA. The delay circuit 20 is constituted of a monostable FF21, time constant setting circuits 20, 23 and a power ON reset circuit 24. Consequently, the reset signal RS is activated with the delay of the fixed period at the start of maintenance of the hot-line, so that the loading/unloading of the hot-line to/form the unit 5 can be attained.

Description

[Detailed description of the invention] What is this invention? The present invention relates to a plug-in unit system composed of II'Ik plug-in units, and particularly to a plug-in unit system in which maintenance or inspection can be performed by inserting and removing several individual units while the system is online.

[Prior art and its problems]

Generally, as this type of system, for example, a pulse control system as shown in FIG. 3 can be considered. In addition,
FIG. 3 is a block diagram showing an example of a general plug-in unit system. In the figure, 1 is a system bus, and 2 is a bus control unit (BS) that controls the bus.
C), 3 is a central processing unit (CPU), 4 is a memory unit (M), 5 is a digital input unit (Di),
6 is an analog input crab unit (Ai), 7 is a digital output crab unit (Do), and 8 is an analog output crab unit (Ao).
), 9 companiesThis is a power supply unit (POW) that supplies power to each of the above units. Each of the units 2 to 8 has a plug-in mechanism, which allows them to be attached to the system bus 1 at will.

Therefore, the information line from the plant or process side,
Since the information is input from the contacts 51 or the transmitter 61 to the digital input unit 5 and analog input unit 6, respectively, this information is read by the central processing unit (CPU) 3 via the system bus 1 (referred to as input processing). .

). The CPU 3 performs predetermined arithmetic processing based on the control program stored in the memory 4 (referred to as arithmetic processing), and the control output information is sent to the digital output unit 7 or analog output via the system bus 1. It is output to Tagata unit 8 (referred to as output processing) and relay 71
．． Valve 81 and the like are operated. Note that the above control is cyclically repeated.

By the way, in such a control system, in order to improve the operating rate of the system, it is required to perform maintenance and inspection on a predetermined plug-in unit in an online state, or to replace a malfunctioning plug-in unit. However, in such a case, it is necessary that even if the plug-in unit to be maintained is attached or detached in an online state, there will be no adverse effect such as malfunction or stoppage of the control system.

Therefore, the applicant has already developed a method for maintaining this type of plug-in unit online (hot-line maintenance method).
We propose a method as shown in the figure. Incidentally, FIG. 4 is a configuration diagram showing a previously proposed plug-in unit system having an online maintenance function.

The explanation will be given below based on FIG. 4.

The figure shows an example of the digital input crab unit 5 in Fig. 3, in which the power supply and reset signal supply sub-connector shown at 10 is connected to the plug-in unit side connector (called a maintenance connector) shown at 11. , a method of hot-inserting and removing the plug-in unit 5 while supplying power and a reset signal. That is, by blocking the output to the system hub 1 by the reset signal 88, electrical disturbances during insertion and removal are prevented, and when the sub-connector 1o is inserted and removed, the live wire is A maintenance interrupt generation circuit 12 is provided which generates a maintenance interrupt signal IN indicating the start and end of maintenance.
By notifying the CPU 3 via line 15,
During online maintenance work, the CPU 3 is prevented from accessing the plug-in unit 5 under maintenance, and the data valid signal (slave unit (Di, Do, Ai
, Ao) to the master unit (CPU)) is intended to prevent a bus connection due to non-reply of a so-called ready signal sent back to the master unit (CPU), or to prevent system stoppage due to this.

However, in this conventional method, while the CPU 3 is accessing the plug-in unit to be subjected to live maintenance (in other words, in the figure, the data read signal RD generated by the data read operation by the CPU 3 becomes valid, and the digital input When the data from the circuit 14 is being outputted to the data bus 16 via the bus driver 17), the reset signal R is inserted into the connector 11.
5 is valid ('0'' is valid), and the bus driver 17
is in a blocked state and output is cut off in the middle of access. In such a case, the CPU 3 uses the plug-in unit 5.
This will result in the data being read without being able to reliably receive the data, leading to system malfunction. In addition,
This operation occurs in the same way when the analog input crab unit 6 is hot-wired and removed using the conventional method.

In other words, it is not possible to simply generate an interrupt signal IN to the master unit at the start of live-line maintenance as in the conventional method.
This has the inherent problem that data transfer between the master unit and the slave unit cannot be terminated normally.

[Purpose of the invention]

The present invention has been made to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide a plug-in unit system that does not adversely affect the operation of a control system and has a more reliable live wire measuring function.

r as a decoy) This invention provides at least one of a plurality of plug-in units.
One is a mask unit and the other is a slave unit, and these are arranged in parallel on a common bus, and in order to access a desired slave unit from the master unit and perform predetermined control, the slave unit has a main plug-in mechanism. By providing a separately provided sub-connector that supplies the power supply voltage and a reset signal (maintenance signal), and a means for notifying the master unit of the start and end of live-line maintenance when the sub-connector is connected/disconnected, it is possible to In a plug-in unit system that prevents the slave unit from being accessed by the mask unit during electrical disturbances or live-line maintenance, a reset signal (maintenance signal) is supplied from the sub-connector or generated when the sub-connector is inserted. ) by a certain period of time that can be determined by the control system, it is possible to prevent erroneous data output that may occur when the start of live maintenance of a slave unit overlaps with the master unit's access to the slave unit. This is to prevent system malfunctions or stoppages.

[During the implementation of the invention]

FIG. 1 shows an embodiment of the present invention, and like FIG. 4, the system bus 1 and digital input unit 5 are mainly illustrated.

In the figure, the digital input crab knit 5 has a maintenance connector 11. It has a configuration in which a delay circuit shown at 20 is added to a conventional circuit (FIG. 4) consisting of an interrupt generation circuit 12, an input data connector 13, a digital input circuit 14, and a data bus driver 17. Therefore, the digital input crab unit 5 is connected to the system bus 1 by an interrupt signal line 15 and a data bus 16, and by mating the external sub-connector 10 and the maintenance connector 11, the digital input crab unit 5 is connected to the live wire. Maintenance and inspection are carried out in the same way as in the conventional example.

On the other hand, the newly installed delay circuit 20 inputs the maintenance signal MA (a signal called a reset signal in the conventional system) which becomes @OH by connecting the sub-connector 10 to the maintenance connector IIK. Then, after a certain time delay, it has the function of generating a reset signal R8 in order to change from ``1'' to 0''. , a time constant setting circuit using a resistor 23, and a power-on reset circuit 24.

Below, the operation of the actual example will be explained based on Figure III. When performing maintenance and inspection on the digital input crab knit 5 while the system is online, first, the sub-connector 10 for supplying power and ground is inserted into the maintenance connector 11. At this time, the maintenance signal wind changes from '1' to '0', so the interrupt signal IN generated in the interrupt generating circuit 12 is notified to the master unit 1 via the common bus 15. Furthermore, the maintenance signal MA is inputted to the input B of the monostaple 7-rip filter 21 in the delay circuit 20.

Here, the operation of the monostaple flip-flop 21 when the clock CLK is applied to the input A is shown below. (1) When the input B is @1', the irregular table signal CLK applied to the input A is The falling edge activates the seven-nostable operation, which causes the output Q to become '1', and from then on, continuous clock input causes it to become '1'.
Maintain the state of ″.

(11) When the input B changes from 1 to θ, the output Q changes from 1 to 0 after a time determined by the resistor 22 and capacitor 23 (hereinafter referred to as time constant τ). ”.

Therefore, input B of monostaple 7 lipfship 21
When the value changes from @1'' to 0'', the reset signal S becomes 90'' and becomes valid after a certain delay time τ due to the operation shown in (II).

Here, the power-on reset circuit 24 is a circuit that outputs a reset signal when the system power is turned on.◇ With the above operation, the interrupt signal IN is output at the start of live-line maintenance.
It can be seen that after the occurrence of , the reset signal R8 becomes valid with a certain time delay τ. Therefore, the data bus driver 17 similarly enters the output blocking state (gate and G are closed) after a time τ after the start of maintenance, and the digital input crab unit 5 becomes ready for hot insertion and removal.

Next, the operation of this embodiment described above will be explained based on the processing time chart shown in FIG. In addition, the second
The figure shows the operation of the control system shown in FIG. 3 in a time chart with the horizontal axis as the time axis. In the figure, a control cycle (A) shows one control operation (referred to as a processing cycle) before maintenance is performed.
This shows that the CPU 3 in FIG. 3 sequentially executes input processing (30), arithmetic processing (31), and output processing (32).

Now, consider a case where a live line maintenance operation (34) is started while the CPU 3 is accessing the digital input crab unit 5 in the input processing (33) of the control cycle (B). At this time, the maintenance interrupt signal 35 is generated as a pulse and is notified to the CPU 3, but the reset signal R8 in the digital input unit 5 does not become effective immediately due to the above-described operation. Therefore, access to the digital input crab unit 5 of the CPU 3 is completed without interruption, and therefore, there is no adverse effect on the system ◇ Then, the CPU d interrupt is accepted, and the interrupt processing
After performing this, the process returns to input processing 37.

The reset signal 38 becomes valid after a time τ, and it becomes possible to extract the second unit 5 while it is in a live state.

Here, the delay time τ is determined as follows.

Generally, in pre-processing for input processing or output processing, the maintenance status of the input/output crab unit is determined using a table etc. representing the input/output configuration created by interrupt processing.
An input/output crab unit in a maintenance state is configured not to be accessed during its input/output processing. Therefore, the minimum value of the delay time is the time '1 t for each input processing and performance processing.
12, and the maximum value must be set within the time (generally several seconds) from when the sub-connector 1o is inserted until when the plug-in unit 5 is manually pulled out. At the end of live-line maintenance, by pulling out the sub-connector 10 from 11, the maintenance interrupt signal is generated again and the reset signal S (38) also becomes heated at the same time.
Unit 5 starts operating.

The control system returns to normal operation.

As explained above, by delaying the reset signal for a certain period of time at the start of live-line maintenance, it is possible to prevent erroneous output or system stoppage caused by the reset signal being output while the master unit is accessing the slave unit. can.

Note that although the above description has mainly been about the input/output crab unit, the same applies to the memory unit.

〔Effect of the invention〕

According to the present invention, in a live-line maintenance method in which a plug-in unit is inserted and removed while supplying power and a reset (maintenance) signal through a sub-connector, together with a means for notifying a master unit of the start of maintenance when a sub-connector is inserted, By providing means for outputting the reset signal with a certain time delay, the following effects can be obtained.

(1) It is possible to prevent system malfunction or stoppage due to erroneous output of data that would occur if hot-line maintenance is started while the master unit is accessing the slave unit to be maintained. Improves sex.

(2 Furthermore, the same concept applies not only to live-line maintenance of slave units, but also to live-line maintenance of master units in so-called multi-mask systems, where multiple mask units are connected to a common bus and exchange information with each other.) It becomes possible to do so.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of this invention, and FIG.
3 is a block diagram showing a general configuration example of a process control system to which the present invention is applied; FIG. 4 is a conventional plug-in unit with online maintenance function. FIG. 1 is a configuration diagram showing a system. Description of symbols 1... System path, 2... Path control unit (B10), 3... Arithmetic control unit (C
PU), 4...Memory unit, 5...
・Digital input crab knit, 6...analog input crab knit, 7...digital output crab knit,
8... Analeg out crab knit, 9...
Power supply unit, 10...Sub connector, 1
1... Maintenance connector, 12... Interrupt generation circuit, 13... Input data connector,
14...Digital input circuit, 15...
・Interrupt signal line, 16...Data bus, 17.
...Path driver, 20...Delay circuit,
21...Mo/stable 7 ribs 70 ribs, 2
2... Capacitor, 23... Resistor, 2
4...Power-on reset circuit, 51...
...Contact, 61... Transmitter, 71...
Relay, 81... Operating end (valve). Agent Patent Attorney Akio Namiki Figure 1 ta 3 Figure 11A Figure

Claims (1)

[Claims] Each of the VISO slave units is provided with a connector mechanism including a plug and is removable with at least one master unit, and is arranged in parallel with the common bus and controlled by the master unit. a signal generating means for generating a reset signal for resetting equipment in the slave unit, and an interrupt signal for notifying the master unit of the start or end of live-line maintenance; 1. A plug-in unit system characterized in that a reset signal is not outputted at least during access of a slave unit by a master unit to avoid malfunction by providing a delay means for delaying the slave unit by a time of .