KR900001030B1 - Digital controller - Google Patents

Abstract

A digital controller obtains manipulation variable corresponding to a difference between a process variable and its set value based on a predetermined function and parameter. A front panel of the digital controller comprises: first display means for displaying in analog form at least one of the process variable, the set value, and the manipulation variable; second display means for displaying a numerical value of at least one of the process variable, the set value, and the maniplulation variable; first selecting means for selecting the set value, secont selecting means for selecting the manipulation variable.

Description

Digital controller

1 is a diagram for explaining general ratio control.

2 is a diagram showing an example of function construction of a general digital controller.

3 is a perspective view showing the appearance of a digital controller according to an embodiment of the present invention;

4 is a diagram showing an example of the display and the arrangement of switches on the front panel of the digital controller of FIG.

5 is a block diagram showing an outline of the system configuration of the digital controller of FIG.

6 is a flowchart showing the basic operation according to the present invention among the processing routines of the CPU of FIG.

FIG. 7 is a flowchart showing another example of operation related to the present invention among the processing routines of the CPU of FIG.

8 is a flowchart illustrating a function setting routine when performing ratio calculation control.

9 is a diagram showing an example of a function setting for executing ratio control.

10A and 10B are flow charts illustrating parameter setting routines when performing ratio calculation control.

* Explanation of symbols for main parts of the drawings

1, 5: flow detector 13: limiter module

15: PID operation module 30: digital controller

32, 35: display device 37-40: change device

51: A / D converter 52: Busline

53: CPU 54: Memory

56: Phenyl Controller

The present invention relates to digital controllers used in process instruments and the like. In general, when the same product is produced in large quantities in a plant, quality stabilization is a problem. This quality is closely related to process operating conditions and is usually indirect by controlling process variables (hereinafter referred to as PV values) such as temperature, pressure, flow rate, and liquid position to match the desired setpoint (hereinafter referred to as SV values). We aim to stabilize quality.

The digital controller performs control operation of the operation output value (hereinafter referred to as MV value) to match the above-described PV value with the SV value, and this MV value is sent to an operation terminal such as a control valve to affect the PV value. It is.

For example, as shown in FIG. 1, when the ratio control of the flow rate Fb is analogized so that Fb = αFa + β with respect to the flow rate Fa, the rate setter is set to the flow rate Fa detected by the flow rate detector 1. Multiply the ratio α according to (2) and add this and the bias parameter β to calculate αFa + β. Subsequently, the limiter 3 imposes a restriction state on the calculation result, and this limited value is called SV value.

In addition, a control operation is performed such that the flow rate Fb (that is, the PV value) detected by the flow rate detector 5 in the controller 4 matches the SV value described above, and the calculation result (that is, the MV value) is obtained from the controller 4. 6), the control valve 6 is adjusted.

Digital controllers perform these ratio calculations, limits, and computational controls all on one machine. Therefore, in order to process the flow rate Fa (Fb) (analog pressure) detected by each flow rate detector (1) (5), what function is provided to the digital controller, and what parameters are operated in the digital controller in advance. You need to set it.

2 is a diagram showing an example of a functional configuration of the digital controller 10 for performing the above-described ratio control. That is, the flow rates Fa and Fb are input to the digital controller 10 as signals proportional to the square of the flow rate by a differential pressure transmitter (not shown).

First, the open calculation modules 11a and 11b are prepared, whereby the signals Fa and Fb are open-ended and linearized. Next, in the ratio / bias module 12 in which the desired ratio α and bias β are set, ratio calculation is performed using a signal of the flow rate Fb system. In the limiter module 13 in which the limit value is set, the limit is applied to the maximum value and the minimum value of the signal of the flow rate Fb system described above.

However, in the operation mode of the digital controller, a cascade mode (hereinafter abbreviated as C mode) to which SV values are applied from the outside, an automatic mode (hereinafter abbreviated as A mode) to operate at partial SV values, and an operator directly operate the MV. There is a manual mode for manipulating the value (hereinafter abbreviated as M mode). Therefore, when the switch module 14 is installed and the C mode is operated, the contact S ₁ is selected, and when the A mode is operated, the contact S ₂ is selected. When the contact S ₁ is selected, αFa + β becomes the SV value, resulting in ratio control.

On the other hand, when the contact S ₂ is selected, the SV value becomes a partial SV value set by the panel surface or the keyboard of the digital controller 10 and eventually becomes the stationary control of the flow rate Fb. In the PID operation module 15 in which the parameters of proportionality (P), integral (I) and derivative (D) are set, the linearized flow rate Fb is set as the PV value, and this PV value is compared with the SV value described above. Perform PID control operation on the deviation and determine the MV value.

By the way, the above-mentioned function was constructed by using a separately installed device called a system loader (RPOM recorder) to record necessary information in a system PROM and to install it in a digital controller. The system PROM described above is mounted on the side of the controller.

When the power switch of the controller is turned ON, the contents recorded in the above-described system PROM are transferred to the RAM in the controller, whereby the digital controller is operated.

In addition, setting and changing of parameters are performed by, for example, the operation of a keyboard installed on the panel next to the controller or an externally attached keyboard.

Conventional examples as described above are for example USP 4,528,623 issued July 9, 1985 or USP 4,542,452 issued September 17, 1985.

As described above, in the conventional digital controller, a special device such as a system loader is required for a function configuration, and a special keyboard is required for setting and changing parameters. In general, the digital controller exposes only the front panel of which the area is limited, and is otherwise stored in a case or rack. Therefore, when setting functions and parameters, the digital controller had to be taken out of the case, and then the device and keyboard of the system PROM had to be operated, and it was cumbersome and the operation was very bad.

Conventional techniques that can be alleviated to some extent include the USP 4,514,798 issued on April 30, 1985, but the control of the US patent requires the opening and closing of the front panel cover to set the functions and parameters. It was not satisfactory as it was done.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital controller capable of improving the operability since the setting of functions and parameters can be performed only by operation of the front panel having a limited area.

The present invention provides display devices 32 and 35 capable of displaying at least one of a process variable value, a set value, and an operation output value for achieving the above-mentioned object, and an angle for changing the above-described setting value, operation output value, and operation mode. Equipped with a change device 37-40 in the front funnel (FIG. 4) and moving to any function setting mode or parameter setting mode (ST _{10 in} FIG. 6) by any of the above-described change devices or a combination thereof. By displaying or setting a function or a parameter by any one of the display device and each of the above-described changing devices or a combination operation thereof (ST ₂₀ ), the above-mentioned by any of the above-described changing devices 40 or a combination operation thereof. This is to disable the function setting mode or the parameter setting mode (ST ₄₀ ).

Next, the embodiments will be described in detail.

3 shows the external configuration of the digital controller 30 in one embodiment of the present invention. This digital controller 30 has a panel surface 31 on its front surface. Moreover, the mode shift command switch 370 may be provided on the side of the controller as necessary.

4 is a front view showing the configuration of the panel surface 31 described above. The panel surface 31 has LED bar graphs 32a, 32b and 32c for displaying PV value, SV value, and MV value, respectively, and individual LEDs 33 (HALT display, ALARM display) for displaying the status of the controller. Computer display (CMP) display mode (RM), display indicator 34 and display 35 and PV 35, SV and MV values as appropriate. Numeric display item display LEDs 36 (for example, red to display PV values, green to display SV values, green to display MV values, and OFF to display MV values) SV setting switches (37a) (37b) for setting and changing values, and mode switching switches (38a) (38b) (38c) and (38c) for switching the operation mode to C mode, A mode, and M mode, respectively. Manual operation switches 39a and 39b for operating the MV value in the M mode, and these manual operation switches 39a and 39b. If used simultaneously with the change speed of manual operation at high speed, and used alone, the item shown on the display 35 is changed from the PV value at SV value. It consists of a FAST / SEL switch 40 or the like that changes to a value.

In addition, the scale bar of the LED bar graphs 32a-32c in the above-described indication indicator 34 has a function setting (determining which action is to be performed) and parameter setting (operating with any parameter) of the digital controller 30. The necessary cross-section 41 is determined in correspondence with the setting items.

For example, a symbol for designating the type of digital controller 30 (e.g., R-SV indicating a PID controller with a 'PID' SV value remote indicating a 1 input 1 output PID controller) is printed on the top, and The symbol for designation (e.g. 'ROT' for flat calculation module, 'LMT' for limiter module, etc.) is printed in the middle, and the symbol for parameter setting (e.g. deviation alarm set value 'DV', derivative time 'TD' ', Integral time' TI 'of PID operation, proportional gain' KP 'of PID operation, etc.) are printed on the bottom.

In addition, the above-mentioned symbol 41 is printed in a color which is not more prominent than the numbers or scales of the scale plate, and when the indication display system 34 is viewed at a slightly separated position, the symbol 41 is considered to be almost invisible.

In addition, what is indicated by the symbol on the panel surface of FIG. 4 is listed below.

PID: PID Controller

R-SV: Remote Set Point

TRK: Tracking (output controlled to next input)

A / M: Auto / Manual

ROT: Flat calculation module

D / R: Forward / Reverse Direction (Output increases in the reverse direction when SV-PV <0. Output increases in the reverse direction when SV-PV> 0.)

RB: Ratio / Bias

LMT: Limiter Module

DV: alarm for deviations from SV-PV

PL: Low alarm point of PV

PH: High alarm point of PV

RL: bottom range of PV

RH: upper range of PV

TD: derivative time of PID operation

TI: Integral time of PID operation

KP: Proportional gain constant of PID operation

5 is a block diagram showing main parts of the system configuration in the present embodiment. In this figure, # 51 is an A / D converter for converting the analog inputs PV ₁ , PV ₂ , into digital quantities, and the signal digitally converted by this A / D converter 51 is the bus line 52. Is given to the CPU 53 through.

The CPU 53 executes a well-known suggestion operation on the input from the A / D converter 51 described above in accordance with a desired function and parameter recorded in the memory 54. It is output from the MV value output part 55 to the control part (for example, the control valve 6 of FIG. 1).

Reference numeral 56 is a panel controller which inputs signals from the switches 36-40 on the panel surface 31 described above, and outputs data of the signals inputted through the bus lines 52 to the CPU 51. There is a function to control display to each display unit 34-36 by the function and the instruction from the CPU 51. Then, in accordance with the signal input to the CPU 53 through the panel controller 56, the functions and parameters of the controller recorded in the memory unit 54 described above can be set.

Next, the outline of the invention in the process performed by the CPU 53 of FIG. 5 will be described with reference to the flowchart of FIG. 6. The CPU 53 is supplied with a mode shift command signal for instructing a shift to a parameter or function setting mode through the panel controller 56.

The mode move command signal is generated by turning on the mode move command switch 370 provided on the side of the digital controller 30 in FIG. 3 or by two SV setting switches 37a provided on the front panel 31 of the controller 30. (37b) is generated by turning ON at the same time.

When a mode move command signal is generated (Yes in ST 10 in FIG. 6), the processing routine is transferred to the CPU 53 to the parameter / function setting mode ST ₂₀ .

While the desired parameters and functions are set in this mode, but while this setting is not completed (NO in ST ₃₀ ), the processing routine of the CPU 53 remains in the parameter / function setting mode. After setting the desired parameters and functions, the parameter / function setting mode is released when the FAST / SEL switch 42 on the front panel 31 is turned on in FIG. (ST ₃₀ , Yes). In this way, the processing routine of the CPU 53 returns to the normal processing mode, and the original arithmetic processing is performed (ST ₄₀ ).

In addition, when the mode move command signal is not generated (NO of ST ₁₀ ), the steps of ST ₂₀ and ST ₃₀ are not executed.

FIG. 7 shows an example different from FIG. 6 as a processing routine performed by the CPU 53 of FIG. The CPU 53 determines the presence or absence of a signal indicating a movement command from the signal input through the normal panel controller 56 to the function setting mode or the parameter setting mode (ST ₁₀ ). If there is no signal indicating the mode movement command (NO in ST ₁₀ ), normal operation control processing is executed (ST ₄₀ ). On the other hand, when a signal indicating this mode moving command is input (YES in ST ₁₀ ), the process shifts to the parameter setting mode first.

If the ST signal ₂₁ is then able to enter again represents the modal movement command without being Modal is released (NO at ST ₃₁₎ (Yes in ST ₁₁₎ moves to the function setting Modal (ST _22). Thereafter _, whenever the signal indicating the mode movement command is input to the CPU 53 (Yes of ST _{11 and} ST ₁₂ ) without the mode being released (NO of ST _{31 and} ST ₃₂ ), the parameter setting mode (ST ₂₁ ) and the function The setting modes ST ₂₂ are switched with each other.

On the other hand, when the signal input to the CPU 53 through the panel controller 56 during the parameter setting mode or the function setting mode includes a signal indicating a release command of the function and parameter setting mode (Yes of ST _{31 and} ST ₃₂ ) Move to the normal operation processing mode (ST ₄₀ ) and execute the operation processing.

In this embodiment, the movement command to the function setting mode or the parameter setting mode is output by applying pressure by simultaneously pressing both of the above-described SV setting switches 37a and 37b. In addition, the command for releasing the function setting mode or the parameter setting mode is output by applying pressure by pressing the above-described FAST / SEL switch 40, for example.

On the other hand, in the function setting mode or the parameter setting mode, the SV value indicating LED bar graph 32b on the panel 31 is switched from the bar graph display to the dot display to indicate any of the predetermined symbols 41. It is supposed to be. In addition, the display 35 displays a number necessary for function setting or parameter setting, and the number can be changed by the operation of the SV value setting switches 37a and 37b.

Next, a case of a controller that performs ratio calculation as an example of a function and parameter setting operation performed using the panel surface 31 will be described in detail with reference to FIGS. 8 to 10.

In FIG. 8, when setting the display mode from any state ST100, if both of the SV setting switches 37a and 37b are pushed twice simultaneously to apply pressure (Yes of ST102), the mode is calculated. From the processing mode to the function setting mode (ST104), the SV value display LED bar graph 32b becomes a dot display, and the symbol 41, for example, the PID of the setting type of the current controller is displayed (ST106).

At the same time, the display 35 shows the type number N = 1 indicating the PID controller. (ST108). In addition, the LED 36 for displaying the number display item lights red. (ST110).

Since the ratio control is now performed by the digital controller 30, the controller 30 must designate the MID controller (R-SV) semicircle (for example, type number N = 2) to which the SV value mode is attached. Thus, when pressure is applied by pressing the SV setting switch 37b (ST112 Yes), the number (LS1 in this case) of the lowest digit LSD displayed on the display 35 blinks (ST114).

Subsequently, if the SV value setting switch 37a is continuously pressed (Yes of ST116), the number during blinking increases (ST118).

Then (NO in ST120) is increased (ST118) and flashes at N = '2' (Yes in ST120), the switch 37a described above is disconnected (NO in ST116).

In this case, N = '2' is displayed on the display 35 (ST112), and 'R-SV' of the LED value 41 of the bar graph 32b for indicating SV is indicated by dots (ST124).

Next, when the pressure is applied by pressing the SV setting switch 37b (Yes of ST126), the setting is enabled and the numeric display item indication LED 36 changes from red to green (ST128).

In this state, when the FAST / SEL switch 40 is pressed (YES in ST130), data N = '2' is set in the CPU 53 (ST132), and the LED 36 described above is changed from green to red ( ST134), data is set.

The type of digital controller 30 is set by the processing routine of FIG. 8, and then the detailed functions are set as shown in FIG. That is, the presence or absence of various processes regarding the controlled amount PV ₁ or the auxiliary analog input PV ₂ is set by selecting "0" (nothing) and "1" (existing).

The initial value is set in advance, and in this case, it is set to "0". In the case of controlling the flow rate here, it is necessary to change the whole designation shown in FIG. 9 from "0" to "1".

The change from "0" to "1" may be the same as the type setting described in FIG.

That is, for example, in the case of setting the flat calculation module, by pressing the switch 37b to apply pressure (ST112), the lowest digit LSD of the display 35 flashes (ST114), and then continuously presses the switch 37a. (ST116). If the number indicating the blinking number (ST118, open operation module &quot; Y &quot;) is displayed (for example, &quot; 1 &quot;) (ST120 Yes), the switch 37a is removed (ST116 NO).

Subsequently, the switch 37b is pressed again to apply pressure (ST126), and when the setting is allowed (ST128), the FAST / SEL switch 40 is pressed to apply pressure (ST130). Thus, the open calculation module is set (ST132). In addition, it is possible to distinguish between setting the open calculation module for the input PV ₁ or setting the open calculation module for the input PV ₂ or limiting the point display by the bar graph 32b.

In other words, for the function selection related to PV ₁ input, the dot display on the LED bar graph 32b should be one point, and for the function selection related to the PV ₂ input, the dot display on the LED bar graph 32b is two points.

After the type setting and detailed function setting of the controller are finished as described above, the FAST / SEL switch 40 is pressed to apply pressure (ST 138 Yes). This releases the function setting mode and shifts to the normal operation processing mode (ST200).

Subsequently, in the case of setting parameters in the calculation processing mode ST200 in FIG. 10A, both of the SV setting switches 37a and 37b are pressed simultaneously to apply pressure (ST202 Yes).

Then, it becomes the parameter setting mode (ST104), and the LED bar graph 32b becomes a dot display, indicating the "KP" of the symbol 41 (ST206).

At the same time, the present proportional gain, for example, "2.00" is displayed on the display 35 (ST208), and the numeric display item display LED 36 lights red (ST210).

In this case, when the parameter setting item is changed, pressure is applied by pressing the SV setting switch 37a (ST212 Yes).

In doing so, the dot display of the LED bar graph 32b moves upward (ST214), whereby the number according to the parameter is displayed by the number of the display 35 (ST216).

On the other hand, for example, when changing the parameter of the proportional gain 'KP' (initial value 2.00), the pressure is applied by pressing the SV setting switch 37b (ST218 Yes). If you do so, the number '2' of the highest digit (MSD) that can be changed will blink (SD220).

When the pressure is applied by pressing the SV setting switch 37a (ST222 Yes), the blinking display number increases (ST224). If it flashes by the desired number Nx (ST226 Yes), the switch 37a is removed (ST228).

Then, if pressure is applied by pressing the SV setting switch 37b (ST230 Yes), the number of flashing pressures is gradually lowered to the lower digit by the number of pressing pressures (ST232). If the desired digit (Dx) is flashing (ST234 Yes), turn off the switch 37b (ST236), then press the switch 37a to apply pressure (ST238 Yes) to the desired digit (Dx). When the numerical value Nx is increased (ST240), and the desired numerical value is obtained (ST242 Yes), the numerical value is set by turning off the switch 37a (ST244).

Here, in FIG. 10B, in the case of the parameter including the decimal point, the current decimal point blinks after the lowest digit blinks to select the decimal point. When the pressure is applied by pushing the SV setting switch 37a in this state (ST254 Yes), the position of the decimal point is pushed from the left to the right (ST256).

At the desired position (ST258 Yes), remove the switch 37a (ST260) and set the position at the decimal point. In this way, when the setting of the lowest digit or the decimal point is completed, the pressure is applied by pressing the SV setting switch 37b (ST262 Yes).

By doing so, the numeric display and the item display LED 36 change from red to green (ST264), and the state can be set. At this time, if pressure is applied by pressing the FAST / SEL switch 40 (ST266 Yes), the changed parameter is set (ST268), and the numerical display and the item display LED 36 return to red (ST272).

Then, when the FAST / SEL switch 40 is pressed to apply pressure (ST266 Yes), the processing returns to the normal processing mode ST276.

As described above, according to the present exemplary embodiment, the function setting and the parameter setting of the controller can be performed by operating the 37a, 37b and 40 while watching the display sections 34-36 provided on the front panel surface 31 of the digital controller 30. Can be.

Therefore, the controller side does not need to set functions and parameters by operating the keyboard or the system (PROM) as in the prior art, so that the entire operation can be performed on the front panel surface 31, and the digital controller 30 is used as a case. There is no need to take it out, and the operability can be improved.

It also eliminates the need for special equipment such as system loaders (PROM writers) to build functions, and eliminates the need for a parameter setting keyboard, making it possible to create a fully functional digital controller at a relatively low cost.

Printing only simple symbols 41 on the LED bar graphs 32a-32c in this embodiment is an added component than in the prior art, but this fact hardly affects the price. Moreover, the present invention is not limited to the embodiment described above.

For example, in the above-described embodiment, the movement to the function setting mode or the parameter setting mode is performed by the operation of the SV setting switches 37a and 37b, and the setting of the functions and parameters is displayed on the display sections 34-36. According to the contents, the SV setting switches 37a and 37b are also operated, and the return to the normal operation processing mode is shown by the operation of the FAST / SEL switch 40. However, the present invention is not limited thereto. May be designed to move, set, or release the mode by operating a switch group of any one provided on the panel surface 31.

In addition, the movement to the function setting mode or the parameter setting mode may be provided by newly installing a dedicated switch (370 in FIG. 3).

In this way, the digital controller 30 can push the harness SV setting switches 37a and 37b unsteadily while performing normal arithmetic operations to prevent pressure from affecting the processing. There is no problem as it is only.

In addition, in the above-described embodiment, the symbol 41 is provided as an instruction for setting the function and the parameter. However, the symbol 41 is not limited to the symbol of the above-described embodiment. Other symbols may be applied as long as they can function as a dragon.

It goes without saying that various modifications can be made without departing from the scope of the present invention. The summary of the above description is as follows.

A front panel is provided with a display device capable of displaying at least one of a process variable value, a set value, and an operation output value, and each change device for changing the above-described setting value, operation output value, and operation mode.

Each of the above-described changing apparatuses is shifted to either the function setting mode or the parameter setting mode by any device or combination operation ST10 thereof.

One of the above-described display apparatuses and each of the above-mentioned changing apparatuses displays and sets the function or parameter by a combination operation of the apparatus (ST10), and sets the function stated by any one of the above-described changing apparatuses or the combination operation thereof. The mode or parameter setting mode is released (ST30).

In this way, the functions and parameters can be set only by operation of the front panel, so that the operation can be improved and a digital controller can be manufactured at low cost.

Claims (9)

A digital controller which produces an operation output value corresponding to a deviation between a process variable value and its set value in accordance with a predetermined function and a predetermined parameter, the point panel 31 of which the process variable value PV, set value SV and First display devices 32a-32c for displaying one or more of the operation output values MV, and for displaying one or more of the above-described process variable values PV, set values SV, and operation output values MV. The second display device 35, the first designating devices 37a and 37b for designating the above-mentioned set value SV, and the second designating devices 39a and 39b for designating the above-described operation output value MV. And a third designating device (38a-38c) for designating the operation modes (C, A, M) of the digital controller described above, the digital controller moving the mode of the digital controller to the function and parameter setting mode. Mode moving device (51-56 in FIG. 5; ST10 in FIG. 6) and the above-described first and second display devices Function / parameter setting display device 51-56 (ST20) for setting the above-described functions and parameters and displaying the setting according to the display and the instruction by at least one of the above-mentioned first to third designating devices, the foregoing Mode return device 51 for canceling the aforementioned function and parameter setting mode and returning to the operation modes C, A, and M of the aforementioned digital controller according to an instruction by at least one of the first and third designating devices. -56; digital controller, ST30). 2. A digital controller according to claim 1, wherein the mode movement due to the mode mover described above is made in accordance with an instruction due to one or more of the above described first to third designated devices. The digital controller according to claim 1, wherein the digital controller includes a mode move command switch 370 in a predetermined portion other than the front panel 31, and the mode move command switch (see FIG. 370) by the ON of the digital controller. The digital controller according to claim 1, wherein the first display devices (32a-32c) described above are provided with symbols (41 in FIG. 4) designating the types of the predetermined functions and the predetermined parameters described above. 2. The function setting apparatus ST22 according to claim 1, wherein the function / parameter setting display apparatus (ST20 in FIG. 6) described above sets the above-described predetermined function by the mode moving apparatus (ST11 in FIG. 7). Digital controller comprising a. The apparatus according to claim 1, wherein the above-described function / parameter setting display device ST20 includes a parameter setting device ST21 for setting the above-mentioned predetermined parameters by the above-described mode moving device (ST10 in FIG. 7). Digital controller characterized by. The method of claim 1, wherein the above-described first designating device includes a first setting switch 37a and a second setting switch 37b provided on the front panel 31, and is operated by the above-described mode moving device ST10. The transition to the above-described function and parameter setting mode is made by turning on both of the above-described first and second setting switches 37a and 37b (ST102 in FIG. 8, ST202 in FIG. 10A), and the predetermined The function selection and the predetermined parameter setting described above are made by the above-described first or second setting switches 37a and 37b (ST112-ST128 in FIG. 8, ST212-ST252 in FIG. 10a and 10b). Digital controller. The front panel (31) according to claim 1, wherein the front panel (31) cancels the mode movement to the function and parameter setting mode described above and returns the digital controller to the mode before the mode movement (ST138 in FIG. 8, ST262 in FIG. 10b). And a release switch (40). The display panel according to claim 1, wherein the display value of the above-described second display device 35 includes any one of the above-described process variable value PV, set value SV, and operation output value MV. A digital controller, characterized in that (36) is provided near the second display device (35) described above.

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