JPS60195618A - Display device of process state signal - Google Patents

Abstract

PURPOSE:To eliminate the necessity of execution of a program for detecting changes in process state in a programmable controller so as to monitor the process state accurately and quickly, by executing the program at a monitoring device controlling section. CONSTITUTION:At a monitoring device controlling section 5 a machine language subroutine 51 reads a process state signal 1 in accordance with an inputted address, compares the signal 1 with the content of a process state signal table in the controlling section 5, and, if a state change is found, sets an apparatus No. corresponding to the changed process signal, its state signal, and the number of the state-changed apparatuses in a state change data table. In addition to the above, the subroutine 51 also sets a logic ''1'' in a state change memory and modifies the content of the process state signal table to make the content coincident with the process state signal read this time. At a state display program (BASIC) 52 the logic ''1'' of the state change memory is judged and only the part of a refresh memory corresponding to the state-changed process state signal is updated. Therefore, the refresh memory which is always updated to correspond to the present state of the signal 1 is read out and displayed on a CRT.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a process status signal display device that displays graphics corresponding to process status signals when performing process control and monitoring of a plant.

[Prior art]

FIG. 1 is a block diagram showing the system configuration of a conventional device, in which (1) indicates a process status signal, (2)
(3) is a process control signal output from the programmable controller (2); (4) is a transmission cable; (5) is a monitoring device control unit; (6) is a cathode ray tube display device (hereinafter abbreviated as CRT), and (7) is an Ifi keyboard.

A monitoring device is configured by (5), (61, and (7)).

Fig. 2 shows an example of the figure displayed on the CRT (6) of Fig. 1.
, V-6, M-7 each represent the equipment number, v-1 to v-3 are input valves, v-4 is a temperature increase valve, V-5 is a cooling valve, ■-6 is an extraction valve, M -7 represents a stirrer. The process state signals corresponding to the process state signal (1) in FIG. 1 are determined for each equipment number in FIG. 2, and the process state signals corresponding to v-1 to M-7 are II, I2, I3, I4, I5
, I6 and I7. For convenience of explanation, it is assumed that these process status signals are expressed as 1-bit binary signals (that is, contact signals in the form of on and off).
The logic of these process status signals 11111 to F is input to the programmable controller (2) and stored, and a graphic as shown in FIG. 2 is displayed on the CRT (6) based on this stored data.

Next, the operation of the apparatus shown in FIG. 1 will be explained. The programmable controller (2) stores the process state signal input at a predetermined sampling period, compares the memory of the previous sampling time with the input of the current sampling time, and changes the process state signal (from logic "o" to logic Check whether there is a change to "1" or a change from logic "1" to logic rOJ (hereinafter referred to as a change in condition), and if there is no change, leave it as is; if there is a change in condition, check whether there is a change in condition. sets a logic "1" in the state change memory indicating that there has been a state change.

The monitoring device control unit (5) constantly checks the status change memory via the transmission cable (4), and when it detects that the logic is "1", it transmits the process status from the programmable controller (2) via the transmission cable (4). The signal ill is read and the displayed figure on the CRT (6) is updated according to its contents. CRT (6) The means for displaying figures on CRT
(6) Similar to the means for displaying characters on the CRT, the figure code corresponding to the partial figure is the CRT on which the partial figure is to be displayed.
(6) The refresh memory, which is stored at the address position corresponding to the position on the screen, and the font memory, which stores the dot pattern of the figure using the figure code as the address, are biased and synchronized with the sweep of the CRT (6). It is well known in the art to read a graphic code from a refresh memory, input the graphic code to a font memory, and display the dot pattern output from the font memory on a CRT (6). process status signal fil
The contents of the refresh memory are determined according to the logical state of the refresh memory.

Conventional devices operate as described above, so even if the monitoring device control unit (5) learns that a change in condition has occurred, it cannot tell which device the condition has changed based on the logic set in the condition change memory. First, all process status signals (1) must be input to edit the refresh memory, which has the drawback of slowing down the status display update speed.

In addition, since the status change memory is set on the programmable controller (2) side, a program for this is required on the programmable controller (2) side, and a program for updating the status display is required on the monitoring device side and the programmable controller (9)11. The disadvantage was that both were required.

[Overview of the invention]

This invention was made in order to eliminate the drawbacks of the conventional ones as described above. In this invention, the state change detection program that was conventionally executed in the programmable controller is executed on the monitoring device side (in the wholesale department, Therefore, a process status signal table is provided in the monitoring device control section, and the status change detection program is executed as a machine language subroutine in the status display program.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a block diagram showing an embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same or corresponding parts, and (51
) is a machine language subroutine, and (52) is a status display program (hereinafter abbreviated as BASIC) written in the RASIC language. The system in Figure 3 is the same as the system in Figure 1 (CRT (6) and keyboard (7) are connected to the monitoring device control unit (5), but (5), (6)
, (7) are the same in the system in Figure 1 and the system in Figure 3, so Figure 3 shows the CRT
(6) and keyboard (7) will be omitted, and their explanation will also be omitted.

FIG. 4 shows BASIC (52) stored in the program memory of the monitoring device control unit (5) and read out and executed.
This is a flowchart showing each step of the machine language subroutine (51). 7.01) to 翰 are the respective steps, of which step Q←l constitutes a machine language subroutine.

At step αη, the start address of the machine language subroutine (51) is set, and at step (a), the input address of the process status signal fil (II to I7) is set as a variable. At step (to), the machine language subroutine (51) is called, and steps 94 to 94 are executed. The called machine language subroutine (51) reads the process status signals (III to F) based on the input address set in step 02, and sends them to the monitoring device control unit (5).
The state change is checked by comparing the contents of the process state signal table (not shown) (corresponding to the previously read process state signal) provided in the process state signal table (not shown) (step (19)
). If the determination in step αQ is Yes, the equipment number (1 in the example of FIG. 2) corresponding to the changed process status signal is
7), its status signal, and the number of devices in which the status has changed are set in the status change data table (not shown).Step Qη), status change memory (not shown) In step M), the contents of the process state signal table are modified to match the process state signal read this time in step (6)), and then the process returns to RASIC (52).

Also, if the determination at step αG is NO, step (
b) After resetting the K depression memory, RASIC (
Return to 52).

In step (b) of RASIC (52), the logic of the state change memory is checked, and if the logic is "0" (the judgment in step el is NO), the process returns to step (to) and the logic is "1".
” (the judgment in step (c) is Yes), then
In step (2), refer to the status change data table set in step αη, update only the part corresponding to the process status signal in the refresh memory (not shown), and then proceed to step (to). return.

In this way, the refresh memory, which is constantly updated to correspond to the current state of the process status signal (1), is read out and displayed on the CRT (6).

Note that in the above embodiment, the contents of the refresh memory are CR
Although it is displayed in T (6), it can also be printed on a printer.

〔Effect of the invention〕

As described above, according to the present invention, since the program for detecting a change in state is executed in the monitoring device control unit, there is no need to execute a program related to monitoring and controlling process status signals in the programmable controller. In general, it is easier to create a program, and the updating speed of CRT display graphics is faster than before, making it possible to monitor process conditions accurately and quickly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the system configuration of the conventional device. FIG. 2 is a diagram showing an example of the figure displayed on the CRT display screen of FIG. 1. FIG. FIG. 4 is a block diagram showing an embodiment, and a flowchart showing the operation of the apparatus shown in FIG. 3. (1)...Process status signal, (2)...Programmable controller, (4)...Transmission cable, (5
)...Monitoring device control unit, (51)...Machine language subroutine, (52)...RASIC. (6)...CRT. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A process state signal display device that displays a graphic corresponding to a process state signal for process monitoring of a plant, wherein the process state signal is inputted via a programmable controller and stored in a process state signal table. means for displaying a graphic corresponding to the content of the process status signal table on a cathode ray tube display device of the monitoring device under the control of a RASIC language program built into the monitoring device; means for providing, in the program, a step of setting a start address of a machine language subroutine and a step of calling the machine language subroutine; Compare the contents of the status signal table, and if there is a change in the status signal, write information about the changed status signal to the status change data table, set a status change memory indicating that there is a status change, and write the information about the changed status signal to the status change data table. After modifying the contents of the signal table to match the process status signal input from the programmable controller above,
In addition, if there is no change in the status signal, the status change memo IJt is reset and the program returns to the BASfC language program. and means for updating a refresh memory that stores graphics to be displayed on the cathode ray tube display device according to the contents of the process state signal table.