JPH0368401B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a process control system, and particularly to a process control system that uses a microcomputer, in which a control device and an operating section of this control device are separated, and only a specific control section is controlled. This invention relates to a process control system equipped with functions such as display.

2. Description of the Related Art A conventional one-loop controller, like a conventional analog controller, has an integrated structure of a man-machine interface section and a control circuit section of a panel where an indicator, operation switches, etc. are present.

Such one-loop controllers are extremely useful for performing direct digital control, but they require large instrumentation and
When centrally monitoring process control using a CRT, the man-machine interface becomes redundant, so if you are aiming for panel-less instrumentation (no man-machine is required for each loop), you may want to make the control room more compact, or you may want to use sequence control, etc. This is inconvenient when exchanging information closely with other control devices.

That is, since the one-loop controller has the same man-machine interface as an analog instrument, a system with several loops requires a considerable panel area and causes problems such as duplication of transmission systems.

For this reason, as the reliability of CRT display systems has improved, there has been a strong desire to establish a system that uses CRTs for centralized control and provides man-machine interfaces only for particularly important control loops.

However, even if you simply separate the man-machine interface and the control circuit, connect them with a cable, and make the control circuit a board type, and store them all together in a housing, the lower part of the housing does not contain any data from the process or interface. Cables gather together, making it difficult to route new cables. In addition, when considering maintenance and inspection, problems such as the connection direction of the connector, its wiring, and the routing of the cable have arisen. There were also problems with system expandability.

Furthermore, when the control section breaks down and must be replaced, there is a problem in that the operational output temporarily goes down, which greatly affects the process.

Furthermore, there is a strong demand from users who actually use the controller system that a unit for display and backup is provided only in important control loops, and that this unit can be freely selected and attached to any control loop.

However, even if this unit is simply installed, it is unclear which control loop it is attached to, and especially
Control systems using CRT displays require a means of making decisions on the display side.

Also, when connecting the operating section to any control loop,
There was a high possibility that the plant operator would make a mistake in the input/output part to the operating end to which the operation is connected.

OBJECTS OF THE INVENTION An object of the present invention is to provide a process control system that is configured so that a control section and a separate operating section can be easily connected.

Another object of the present invention is to provide a process control system using a digital input reading circuit that transmits and detects which control loop an operating section is connected to.

SUMMARY OF THE INVENTION In order to achieve this object, the present invention connects the operating section of the control device to any input/output section of the control section, and also connects the operating section to a digital input reading circuit.

Embodiment of the present invention The present invention will be described below with reference to the drawings regarding one embodiment. FIG. 1 is an explanatory diagram illustrating the system configuration of one embodiment. FIG. 3 is a block diagram of the control system of this embodiment.

1-1 to 1-n represented by the control unit 1 have a microcomputer CPU, and input signals from 2-1 to 2-n represented by the detection end 2 are sent to an AD converter A/D.
After converting it into a digital signal, it is processed.

All functional modules for performing input/output calculations and control calculations are written in ROM, and RAM is provided for exchanging information with the host computer and with other control units. M/A is a switching circuit that selects manual control or automatic control from the control unit side. The operation output after the CPU control calculation is outputted by the MVU/D output circuit.
In addition, 3-1, 3- represented by the operation section 3 of the control section
A transmission circuit ART is provided for signal transmission with 2.
These circuits are communicated by an internal bus.

The operation units 3-1 and 3-2 of the control unit 1 are the control unit 1,
It is separated from the casing in which the transmission interface 5 and the like are housed, and placed in an operator console for centralized management. The loop display units, ie, the operating sections 3-1 and 3-2, are provided depending on the needs of the object to be controlled, and are not necessarily provided in number corresponding to all the operating terminals. Furthermore, the control section 1 is not operated only from the display units 3-1 and 3-2.
Of course, it can also be operated using the built-in operation function of the CRT4. Rather, this operation section 3-
1 and 3-2, in this embodiment, the control section 1 can be operated for limited matters such as backing up important loops and displaying the MV and SV values of the loops.

The CRT 4 and each control section 1-1 to 1-n perform data transmission using data transmission interfaces 5, 6, and 7.

Using the operating units 3-1 and 3-2, the operator can use the microphone processor to blink the display when an alarm occurs, display upper and lower alarm set values, and back up PV value instructions in the event of a control failure. In order to execute these functions, the operation units 3-1 and 3-2 include a CPU,
RAM, ROM, D/A converter, etc. are arranged. The connector P connects 8-1 to 8-1 represented by the operation output unit 8, which is the input/output section of the control device.
8-n and the operation units 3-1 and 3-2 are connected.

The operation output unit 8 stores the operation output in an up-down counter U/DC, converts it into analog with a digital-to-analog converter D/A, and outputs the operation output to the operation terminals 9-1 to 9-n. This operation output is output by the M/A of the control section 1 or the operation section 3-
1 and 3-2 select between the manual operation connection output and the automatic control operation output. S1 is a switch which can be switched to automatic control side A or manual operation side M by operating sections 3-1, 3-2 or control section 1. A drive circuit M/A is provided to drive this switch S1.

This operation output unit 8, including not only the D/A converter but also peripheral circuits, is integrated into an IC and is formed in a small size.

10 is a digital input reading circuit, which is connected to the operating section 3-
1 and 3-2, and is an interface that communicates the control units to which the operation units 3-1 and 3-2 are connected to each of the control units 1-1 to 1-n and to the CRT 4 through the bus 6. be.

Further, the connector P is constructed of a pin input type, such as a telephone exchange, so that the operation sections 3-1 and 3-2 can be easily connected to other operation output units. This connector structure P will be explained with reference to FIG. FIG. 4 is an explanatory diagram of the relationship between the operating section 3-1 and the connector P, in which the transmission line of the operating section 3-1 is connected to the connector plug 11-3. The transmission line of each operating section is connected to a connector plug 11-n. This plug has 15 pins, and pins 12 to 15 are for address information of the connector and are connected to the digital input reading circuit 10. The receptacles connected to this plug 11-3 are receptacles 12-1 to 12-n represented by 12, and these receptacles transmit input and output to the operation output units 8-1 to 8-n, respectively. do. Therefore, the operating section 3-1 is connected to the control sections 1-1 to 1-n via the connector plug 11-3 and any one of the receptacles 12-1 to 12-n.

Pins 1 and 2 of the connector are ART (Asynchronous receiver), which is a transmitter/receiver for information transmission.
pins 3, 4, 5, and 6 are in charge of the MVUP signal, MVDOWN signal, manual control selection signal, and automatic control selection signal, respectively.
Pin 7 is also responsible for displaying whether automatic control or manual control is currently selected. Pins 8, 9, 12 respectively PV value, MV value,
Pin 10 is in charge of zero voltage, which is a reference voltage. Pin 11 performs PV selection. Further, the receptacle 12-2 of the connector P is a similar receptacle connected to the operation output unit 8-2.

Then, the operating section is connected only to an arbitrary loop among the control loops, but the receptacles of the other loops that are not connected are connected to the receptacles 12 as shown in Fig. 2b.
20-1 to 20-n represented by the cover 20 on the side
is fitted. Here, FIG. 2a shows the plug 11 and cover 20 of the transmission line of the operation unit connected to the receptacle 12 of the operation output unit, and FIG. 2b shows the cover 20 fitted to the receptacle.
-4 is explained. This cover 20 has written thereon predetermined information about the process control object that the receptacle is responsible for. This process control target predetermined information indicates which process control target, such as temperature, flow rate, pressure, etc., is controlled by the control loop of the control unit of the operation output unit having the receptacle. For example, cover 21-
1 is connected to the temperature control loop and indicates that the display is expressed in °C when the operating section 3 is connected, and the cover 20-3 is connected to the flow rate control loop and indicates that the operating section 3 is connected.
When connected, it indicates the unit of m ³ /h. Currently, in the embodiment shown in FIG. 2, the operating section is connected to the temperature control loop T103 indicated by the cover 20-4. According to this cover 20-4, it can be seen that the display on the operation unit 3 is displayed at ×3, that is, three times the temperature. After this cover is removed from the receptacle as shown in FIG. 2b, it is placed on top of the operating section 3. In other words, the cover can be used in place of the TAGNO plate. The operation section 3-1 performs backup and display of each control loop, directly displays the output from the operation output unit, and outputs an output signal for backup.
It can be used even if it varies depending on the flow rate, temperature, etc.

In FIG. 3, whether or not to input the PV value by passing it through the square root calculation circuit 30 is selected by the information of "0" or "1" of pin 11 in FIG. 4, and switch S2 is selected.
It is determined whether the PV value is displayed as it is and calculated, or it is displayed after square root calculation.

Next, in the process control system configured as described above, when controlling the operation end 9 automatically, normally, the switch S of the operation output unit 8 is turned on.
1 to "A", the operation output from the control unit 1 is held by the counter U/DC, and then exchanged with an analog signal. This is no different from a normal DDC control system.

If the control section breaks down, the operation output unit 8 holds the operation output even if the control section 1 is removed, so that the control section can be easily replaced. Moreover, since the operation output unit is connected to the operation section 3 via a cable, the MV value,
In addition to displaying the SV value, manual control is also possible. At this time, switch S1 from the operation panel.
to manual operation.

When changing the operating section to another control loop, remove the corresponding cover, attach the plug of the operating section, and place the cover near the operating section. This makes it possible to understand the display unit of the operating section. Furthermore, the digital input reading circuit transmits to the CRT which control loop the operating section is connected to.

Effects of the Present Invention As described above, the present invention has an input/output section to the operating end of the process that is structured separately from the control section, and the operating section is connected to this input/output section. Even if a failure occurs, the operating end can be controlled from the operating section, and the operating section can be freely connected to any control loop. This makes it possible to provide an efficient and highly reliable control system.

Furthermore, since the operating section can be selectively used only for the necessary loops, the overall system cost can be reduced.
Moreover, the panel area can be reduced.

Furthermore, with this configuration, operating units can be placed only in important control loops as necessary to perform backups, etc., making large-scale instrumentation using CRTs more realistic and efficient. In addition, it is possible to uniformly perform everything from small-scale instrumentation to large-scale instrumentation.

The connector cover is easy to lose because it is removed and placed when the connector is used, but by using this cover in place of the TAGNO plate on the operation section, you can prevent loss and provide important information to the operator. can.

Furthermore, it is possible to reliably select one of the many input/output units to which the operating unit should be selectively connected.

Therefore, it is possible to prepare a smaller number of operating units for any given control loop and easily back up, display, etc. the control loop.

Furthermore, in the present invention, it goes without saying that the receptacle may be provided directly on the operation output unit.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram illustrating the system configuration of an embodiment of the present invention; FIGS. 2a and 2b are explanatory diagrams illustrating connection of a connector and attachment/detachment of a cover of an embodiment;
FIG. 3 is a block diagram of one embodiment, and FIG. 4 is an explanatory diagram showing an operating section, a connector, and a digital input reading circuit. 1-1 to 1-n...control unit, 3-1, 3-2...
...Operation unit, 8...Operation output unit, 10...Digital input reading circuit, P...Connector.

[Claims]

1. An arithmetic circuit 5 that executes initialization processing when receiving an auto-reset pulse, and outputs a reset signal and a signal for relay activation when a start signal or operation signal is input after completion of the initialization processing; A power outage detection circuit 3 outputs a power outage signal when the power supply 2 that supplies power to the circuit 5 experiences a power outage, and a power outage detection circuit 3 outputs a power outage signal when the power supply 2 that supplies power to the arithmetic circuit 5 returns to a normal state from the power outage. an auto-reset circuit 8 that outputs an auto-reset pulse to the output, a plurality of relays 71...7n that are provided corresponding to a plurality of loads and operate according to signals from the arithmetic circuit 5, and a common line C connected to a power source. A plurality of relay contact outputs 71a...7 are inserted into the lines connecting the and each load, and open and close each line according to the operation of each relay 71...7n.
na, a common line control circuit 9 which outputs a relay off signal when receiving a power outage signal from the power outage detection circuit 3, and outputs a relay on signal when receiving a set signal from the arithmetic circuit 5, and a common line C. A common line control relay 10 which opens the common line contact 10a by a relay off signal from the common line control circuit 9 and closes the common line contact 10a by a relay on signal from the common line control circuit 9. Electronic control unit equipped with.

Claims (1)

[Claims] 1. In a process control system, a plurality of control units that control a plurality of control loops, a number of control units smaller than the number of control units, and an operation unit having separate display and backup functions;
a plurality of input/output units having a function of holding operation outputs separated from the control unit, connected to the control unit and the operation end of the process, and connected to the operation unit by a connector; and the operation unit A digital input reading circuit is connected to the operating section to detect whether the input/output section is connected to any of the input/output sections, and a control loop process control circuit is connected to the connector of the input/output section to the operating section. 1. A process control system comprising: a connector cover on which predetermined target information is written; and the operation section is connected to an input/output section.