JP2000259201A - Analog output device and control system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive analog output device which can eliminate the possibility of large hindrance that is caused by its wrong mounting. SOLUTION: The mode identification information showing a hold mode or a reset mode is previously set at an output mode storage part 22. When the transmission of data is discontinued for a prescribed time or longer, a discontinuation time monitoring part 23 refers to the part 22 to hold the control output value at a level set right before the abnormality is detected or to set the control output value at zero when the mode identification information shows the hold mode or the reset mode respectively. In such a constitution, a common structure is secured for an analog output module 20 which performs both hold and reset modes in regard to an analog output device and a control system that uses this output device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analog output device for controlling, for example, an industrial plant or a public plant, and a control system using the same. The present invention relates to an output device and a control system using the same.

[0002]

2. Description of the Related Art Generally, in a plant control system, P
Configuration including, as hardware used for ID control or the like, a module combining an analog input device (hereinafter, also referred to as an analog input module) and an analog output device (hereinafter, also referred to as an analog output module) or a module having an analog input / output function. Is widely used.

FIG. 11 is a schematic diagram showing a schematic configuration of a plant control system of this type. In this plant control system, a plurality of operator stations 1 and a plurality of control stations 2 are connected to each other via a control LAN 3.

[0004] The operator station 1 has a function of displaying and operating a plant state, and includes, for example, a CRT, a keyboard, and a database device.

The control station 2 is a device for executing a control program for various plant controls such as PID control and sequence control, and a plant input / output. The control station 2 has an input-side I / O module 4 connected to the control LAN 3, Output I / O modules 5 that are not connected to the control LAN 3 are connected to a main control device 7 via an I / O bus 6, respectively.

[0006] The I / O modules 4 and 5 are provided with various modules corresponding to signals such as analog input, analog output, digital input, and digital output.

An arbitrary number of I / O modules 5 on the output side can be controlled by a unified instrumentation signal (4-20) for opening / closing control.
An analog output module 5 a that outputs a mAdc analog current signal) to the operation valve 8.

In the analog output module 5a,
As shown in FIG. 12, the I / O connected to the I / O bus 6
The bus transmission unit 9 is connected to the control unit 10. Control unit 1
0 gives a digital voltage to the D / A converter 11. D /
The A converter 11 converts the digital voltage and supplies a corresponding analog voltage to the voltage / current converter 12. Voltage/
The current converter 12 converts the analog voltage and outputs a corresponding instrumentation unified signal to the operation valve 8 in the field. Note that the voltage / current converter 12 is omitted, and the D / A converter 11
May convert the digital voltage into an analog current instrumentation unified signal and output it to the operation valve 8 in the field.

In such a plant control system, when the analog output of the analog output module 5a cannot be updated due to a failure or the like, a fail-safe operation for shifting to the hold mode or the reset mode according to the control method is performed.

For example, in the field of instrumentation control such as temperature / pressure / flow rate control, the analog output module 5a is shifted to the hold mode when a failure occurs to perform mainly continuous control. Is maintained continuously.

On the other hand, in the field of electrical control such as motor control, in order to mainly perform sequence control, the analog output module 5a is shifted to the reset mode when a failure occurs, and the instrumentation unified signal is turned off (shifted to 0 mA).

Such a plant control system operates uniformly in the hold mode or the reset mode. Note that, even in a configuration in which the hold mode and the reset mode are simultaneously realized, each mode is realized by a dedicated analog output module 5a having a different structure.

[0013]

However, in the above control system, when the hold mode and the reset mode are realized by the same system, there are the following problems.

That is, since the analog output module 5a corresponding to each mode is provided, it is necessary to always have two types of spare modules for abnormal situations, which increases the cost.

Further, if the analog output module 5a corresponding to the different mode is erroneously mounted, there is a possibility that a large trouble will occur in the fail-safe operation at the time of abnormality.

Further, when it is desired to change the specification of the output mode at the time of abnormality, the analog output module 5a is replaced.
However, if the analog output module 5a is replaced during the system operation, the analog output disappears during the replacement period. For this reason, specification change during system operation is impossible. Therefore, the system is temporarily stopped and the module is replaced. Thus, operability and workability during maintenance are low.

The present invention has been made in view of the above circumstances, and provides an analog output device which can be realized at low cost and which can eliminate the possibility of a great trouble caused by incorrect mounting, and a control system using the same. With the goal.

Another object of the present invention is to change the specification of the output mode at the time of abnormality even during system operation,
The operability and workability during maintenance can be improved.

[0019]

According to a first aspect of the present invention, there is provided an analog output device which performs data transmission with a higher-level control device and provides a control output value to a lower-level control object. Mode storage means for setting mode identification information indicating a reset mode,
When the data transmission is stopped for more than a predetermined time, when the mode identification information indicates the hold mode by referring to the mode storage means, the control output value is held at a value immediately before abnormality detection, and the mode identification information is reset. This is an analog output device including stop abnormality monitoring control means for setting a control output value to zero when a mode is indicated.

According to a second aspect of the present invention, in the control system using the analog output device according to the first aspect, the control device includes a control program and an application program for controlling the analog output device. A terminal equipped with an engineering tool for transmitting and receiving the control program, the application program and the device configuration information is registered, and registers device configuration information indicating an arrangement of the analog output device. The engineering tool is a control system including mode setting means for setting the mode identification information in the mode storage means.

According to a third aspect of the present invention, in the control system according to the second aspect, the engineering tool is designated by the device configuration information based on the device configuration information and the mode identification information. And a display processing unit for displaying the analog output device and the mode identification information set in the analog output device in association with each other.

According to a fourth aspect of the present invention, in the control system according to the third aspect, the analog output device has status sending means for sending its own output status, and the analog output device has the status processing means as the display processing means. Is a control system for displaying the output status obtained from the status sending means and the analog output device specified by the device configuration information in association with each other.

According to a fifth aspect of the present invention, in the control system according to the fourth aspect, as the engineering tool, a reset input for inputting a reset release command together with position information of a target analog output device. The analog output device, upon receiving a reset release command and position information input by the release input means, releases the control of the zero value of the control output value when the position information indicates itself. This is a control system including a mode release unit.

According to a sixth aspect of the present invention, in the control system according to the fifth aspect, the engineering tool includes batch release input means for inputting a batch reset release command, and the analog output The control system includes a batch release unit that releases the control to zero when the device itself controls the control output value to zero upon receiving a batch release command input by the batch release input unit. It is.

According to a seventh aspect of the present invention, in the control system using the analog output device according to the first aspect, the analog output device indicates selection or non-selection for each item related to abnormality monitoring. A selection information storage unit in which selection identification information is stored, and provided for each item related to the abnormality monitoring, and when the selection identification information of the corresponding item in the selection information storage unit indicates selection, the corresponding abnormality monitoring is executed. When the abnormality is detected by referring to the mode storage means, when the mode identification information indicates the hold mode, the control output value is held at the value immediately before the abnormality detection, and when the mode identification information indicates the reset mode, the control output value is stored. A plurality of types of abnormality monitoring control means for reducing
The engineering tool is a control system including selection setting means for setting the selection identification information in the selection information storage means.

The invention according to claim 8 is the control system according to claim 7, wherein the analog output device performs the control when the control output value is set to zero by the abnormality monitoring control means. A descent characteristic storage means in which a descent characteristic of an output value is stored, and a descent control means for lowering the control output value according to a descent characteristic in the descent characteristic storage means when the control output value is set to zero,
The engineering tool is a control system including descent setting means for setting descent characteristics in the descent characteristic storage means.

(Operation) Therefore, in the invention corresponding to claim 1, by taking the above means, a mode storage means in which mode identification information indicating a hold mode or a reset mode is set in advance is provided, When the monitoring control means stops the data transmission for more than a predetermined time and refers to the mode storage means and the mode identification information indicates the hold mode, the control output value is held at the value immediately before the abnormality detection, and the mode identification information is stored. By setting the control output value to zero when indicating the reset mode, the analog output device main body that performs each mode can be shared, so that it can be realized at low cost and it is possible to eliminate the possibility of serious trouble due to incorrect mounting. .

According to a second aspect of the present invention, the control device supports creation of a control program and an application program for controlling the analog output device, and registers device configuration information indicating an arrangement of the analog output device. A terminal equipped with an engineering tool for transmitting and receiving a control program, an application program, and device configuration information is connected. As the engineering tool, mode identification information is set in mode storage means by mode setting means. In addition to the action corresponding to 1, the specification of the output mode at the time of abnormality can be changed even during system operation, and operability and workability at the time of maintenance can be improved.

Further, according to a third aspect of the present invention, as the engineering tool, an analog output device designated by the device configuration information based on the device configuration information and the mode identification information by the display processing means, and the analog output device Is displayed in association with the mode identification information set in (1), the mode setting content can be easily confirmed in addition to the action corresponding to claim 2.

According to a fourth aspect of the present invention, as an analog output device, its own output status is sent out by status sending means, and as the display processing means of the engineering tool, the output status obtained from the status sending means is output. Since the information and the analog output device specified by the device configuration information are displayed in association with each other, the present output status can be easily confirmed in addition to the operation corresponding to the third aspect.

According to a fifth aspect of the present invention, as the engineering tool, a reset release command is input together with the position information of the target analog output device by the release input means, and the mode release means is used as the analog output device. When the reset release command and the position information input by the release input means are received, the control of the zero value of the control output value is released when the position information indicates the self. The reset mode of a desired analog output device can be released online, and labor for going to the site can be omitted.

According to a sixth aspect of the present invention, as the engineering tool, the batch release input means is used.
A reset batch release command is input, and the analog output device receives the batch release command input by the batch release input unit by the batch release unit. In addition to the operation corresponding to claim 5, when the reset mode of all the analog output devices is released, the reset state can be immediately released by one key operation, so that the normal control is resumed. Time to MTTR, and MTTR
(Average repair time) can be reduced.

Further, according to a seventh aspect of the present invention, as the analog output device, selection information storage means for storing selection identification information indicating selection or non-selection for each item relating to abnormality monitoring; When the selection identification information of the corresponding item in the selection information storage means indicates the selection and the abnormality is detected by detecting the abnormality, the mode identification information is referred to the mode storage means and the hold mode is set. And a plurality of types of abnormality monitoring control means for holding the control output value at the value immediately before the abnormality is detected when the mode identification information indicates the reset mode, and setting the control output value to zero when the mode identification information indicates the reset mode. Since the selection identification information is set in the selection information storage means by the setting means, in addition to the action corresponding to claim 1, according to the contents of the control system It is possible to select the contents of the normal monitoring, at the time of abnormality occurs, the impact on the control system can be kept to a minimum.

According to a further aspect of the present invention, as the analog output device, a drop characteristic storage means for storing a drop characteristic of the control output value when the control output value is set to zero by the abnormality monitoring control means. As an engineering tool, the descent characteristic is set in the descent characteristic storage means by the descent setting means, and the descent control means of the analog output device sets the descent characteristic in the descent characteristic storage means when the control output value is set to zero. The control output value is lowered in accordance with the following formula. In addition to the action corresponding to claim 7, the method of lowering the control output value at the time of reset can be selected in accordance with the contents of the control system. A control system can be constructed so as to realize different operations.

[0035]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a schematic diagram showing a configuration of an analog output module applied to a control system according to a first embodiment of the present invention. The detailed description is omitted, and the different parts are mainly described here. In the following respective embodiments, the duplicated description will be omitted in the same manner.

That is, in the present embodiment, the common analog output module 20 can arbitrarily select an output mode in the event of an abnormality. Specifically, the control unit 21 controls the output mode storage unit 22 and the stop mode. It has a time monitoring unit 23, a D / A conversion unit 24 including a voltage / current conversion function has a reset terminal 24r, and an OR logic element 25 is interposed between the stop time monitoring unit 23 and the reset terminal 24r. It has a configuration that allows it.

Here, the output mode storage section 22 stores in advance mode identification information indicating a hold mode or a reset mode as an output mode at the time of abnormality.

The stop time monitoring unit 23 monitors the I / O bus transmission unit 9 and, when there is no access to the I / O bus transmission unit for a certain period of time, if the contents of the output mode storage unit 22 are in the reset mode, outputs a reset signal to the OR logic element. 25 is provided.

The OR logic element 25 has one input terminal connected to the stop time monitoring unit 23, the other input terminal connected to the card internal circuit (not shown), and the output terminal connected to the D / A conversion unit 24. It is connected to the reset terminal 24r. Note that the card internal circuit outputs a power-on signal at power-on.
It has a function given to the R logic element 25.

Next, the operation of the control system configured as described above will be described. Now, assume that the system is started or initialized. The main control device 7 transmits the mode identification information to the analog output module 2 via the I / O bus 6.
Send to 0. The analog output module 20 transmits the mode identification information to the control unit 21 via the I / O bus transmission unit 9.
Is written to the output mode storage unit 22.

Subsequently, the system is in operation. The main control device 7 sends analog output data to the I / O bus 6. The I / O bus transmission unit 9 checks for an abnormality in the analog output data received from the I / O bus 6, and then sends the data to the control unit 20.

The control section 20 sets the output value in the D / A conversion section 24 according to the analog output data.

The D / A converter 24 outputs an instrumentation unified signal (DC analog current signal of 4-20 mAdc) to the operation valve 8 according to the set data.

Next, here, the main control device 7
Here, a case in which the device goes down due to an abnormality will be described. In this case, I
The transmission of the / O bus 6 is interrupted. Therefore, the control unit 21 in the analog output module 20 stops updating the output data as well as controlling the plant until the main control device 7 recovers.

At this time, the control unit 21 monitors the suspension time of the I / O bus transmission unit 9 by the suspension time monitoring unit 23. When the suspension time exceeds a predetermined time, the output mode storage unit 22
When the mode identification information indicates the reset mode, a reset signal is output to the OR logic element 25.

The OR logic element 25 passes the reset signal and supplies it to the reset terminal 24r of the D / A converter 24. Upon receiving this reset signal, the D / A converter 24 shifts to the reset mode, and converts the unified instrumentation signal to zero mA.
And Therefore, the analog output module 20 also shifts to the reset mode, and realizes the reset operation.

On the other hand, when the mode identification information in the output mode storage unit 22 indicates the hold mode, the stop time monitoring unit 23
Does not output a reset signal and does not perform any operation.

As a result, the D / A converter 24 does not update the data from the controller 21, so that the unified instrumentation signal to the operation valve 8 is in a hold state.

As described above, according to the present embodiment, the output mode storage unit 22 in which mode identification information indicating the hold mode or the reset mode is set in advance, and the stop time monitoring unit 23 sets the data transmission time to a predetermined time When the mode identification information indicates the hold mode with reference to the output mode storage unit 22, the control output value is held at the value immediately before the abnormality detection, and when the mode identification information indicates the reset mode, the control output value is reset when the mode identification information indicates the reset mode. By setting it to zero, the structure of the analog output module 20 that performs each mode can be shared, so that it can be realized at low cost and the possibility of a great trouble caused by incorrect mounting can be eliminated.

The common analog output module 20
Thus, the output mode at the time of failure can be set programmable, so that the analog output module 20 of the control system can be standardized. This eliminates the need to have a plurality of types of spare modules for abnormal situations, which is economically advantageous.

(Second Embodiment) FIG. 2 is a schematic diagram showing a partial configuration of a control system according to a second embodiment of the present invention. This control system includes a main control device 7
And a terminal 31 such as a personal computer on which an engineering tool 30 is mounted.

Here, the engineering tool 30
A creation support function for supporting creation of a control program and an application program, a setting function for setting system configuration information (including position information), an output mode (mode identification information), and the like based on the application program; A transmission / reception function for transmitting creation contents, setting contents and input contents (reset release command and reset batch release command, etc.) and receiving the current state, and for displaying creation contents, setting contents and reception contents. It has a display processing function.

The application program selectively displays a mode setting screen 32, a hardware configuration screen 33, an alarm screen 34, a reset release screen 35, and the like on a terminal or an operator station as shown in FIGS. It is for operating each according to the content.

As shown in FIG. 3, the mode setting screen 32 is for setting an output mode for each module of the control system based on the system configuration information.
As shown in FIG. 4, the hardware configuration screen 33 is for displaying the hardware configuration of the control system based on the system configuration information.

The alarm screen 34 is displayed as shown in FIG.
Based on the system configuration information and the current state of each module, an alarm status such as resetting is displayed for each module of the control system.

As shown in FIG. 6 or FIG. 7, the reset release screen 35 displays the reset status of each module of the control system based on the system configuration information.
This is for displaying a reset release icon 36 and a batch reset release icon 37 that allow a reset release command to be input.

The system configuration information includes a system name, a station number (for example, PCS6000), a unit number (for example, UNIT No. 0 to 15), a slot number (for example, 0 to 1).
1), module name (eg, SPSXX, SAOP1, S
LTRX) and contents such as module information (number of output points, output mode, etc.), which are referred to by an application program and used for displaying the screen described above.
When the screen is displayed, the system configuration information is displayed in an appropriate combination with the current state (alarm, output value, etc.) of each module.

Next, the operation of the control system configured as described above will be described. Engineering tool 3
0 causes the terminal 31 to display the mode setting screen 32 in accordance with the operation of the terminal 31 as shown in FIG. Further, mode identification information indicating the output mode is set in the mode setting screen 32 in accordance with the operation of the terminal 31, and when the setting content is determined, the mode identification information is converted to the corresponding analog output based on the system configuration information. Control unit 21 of module 20
Send to

Thus, the mode identification information is set online in the output mode storage unit 22 of the control unit 21.
On the other hand, in the operator station 1, a hardware configuration screen 33 is displayed by the operation of the operator as shown in FIG. On the hardware configuration screen 33, the output mode of each analog output module 20 can be displayed by the application program 30 based on the setting contents of the mode setting screen 32.

Next, a case where the control system is abnormal will be described. As described above, when an abnormality occurs in the main control device 7, the analog output module 20 set in the reset mode in advance shifts to the reset mode, the instrumentation unified signal becomes 0 mA, and the control unit 21 The status (during reset, output 0 mA) is sent to the I / O bus transmission unit 9 addressed to the operator station 1.

In the operator station 1, the alarm screen 3 is displayed by the operation of the operator as shown in FIG.
4 is displayed. On the alarm screen 34, the application program 31 displays the analog output module 20 based on the stop time abnormality detected by the control unit 21, the setting contents of the mode setting screen 32, and the current status received from the control unit 21. An alarm related to the reset mode or the hold mode (example in the figure, RS during reset) and the like are displayed.

As a result, it can be easily confirmed that the reset is being performed and the unified instrumentation signal from the analog output module 20 is still 0 mA. Thereafter, the operation of the main control device 7 recovers and the I / O
Even if the bus transmission resumes normally, the reset state is continued. This is to prevent the effect on the plant when the value of the instrumentation unified signal to the operation valve 8 is automatically restarted.

Subsequently, in the operator station 1, a reset release screen 35 including a reset release icon 36 is displayed by the operation of the operator, as shown in FIG. In the reset release screen 35, when the reset release icon 36 is clicked by an operator's operation, an input window screen for position information for specifying the analog output module 20 to be released is displayed (not shown). ). The input window screen allows the user to input the unit number and the slot number of the analog output module 20 for canceling the reset, for example, in a conversation format.

When a unit number and a slot number are input on this input window screen, a set of a reset release command and position information is sent from the main control device 7 to the analog output module 20 specified by both numbers. The reset is released to the analog output module 20.

Note that all the analog output modules 20
If it is desired to release the reset state at the same time, the reset state may be collectively released by clicking the batch reset release icon 37 as shown in FIG.

After the reset release is completed, in the operator station 1, the output data is set for each analog output module 20 by the operation of the operator, and the control returns to the normal control.

As described above, according to the present embodiment, the main control device 7 supports the creation of a control program and an application program for controlling the analog output module 20, and the I / O of the analog output module 20 and the like. A terminal 31 equipped with an engineering tool 30 for registering device configuration information indicating an arrangement of devices and transmitting and receiving a control program, an application program, and device configuration information is connected. As the engineering tool 30, a setting function is used. Since the mode identification information is set in the output mode storage unit 22, in addition to the effects of the first embodiment, even during system operation,
The output mode specifications can be changed online when an error occurs, and the output mode specifications can be changed online even when the specifications need to be changed or a module needs to be added. Can be significantly improved.

As the engineering tool 30, the display processing function allows the analog output module 20 specified by the device configuration information and the mode identification information set in the analog output module 20 to be determined based on the device configuration information and the mode identification information. And the hardware configuration screen 33 is displayed, so that the mode setting contents can be easily checked, and the presence or absence of a setting error such as a setting change or an error in the added information can be visually checked. .

The analog output module 20 sends its own output status by a status sending function, and the display processing function of the engineering tool 30 uses the output status and device configuration information obtained from the analog output module 20. Analog output module 20 specified
And the alarm screen 34 is displayed, so that the current output status can be easily confirmed.

For example, even if an abnormality has occurred in the main controller device 7 and it has been recovered, the analog output module 20 set in the reset mode is currently being reset, and the instrumentation unified signal of the module 20 is zero m.
It can be easily confirmed that the state is A. Therefore, the maintenance staff does not need to go to the site to check the unified instrumentation signal, thereby improving the work efficiency.

Further, as the engineering tool 30, by clicking the reset release icon 37 or the like,
When the reset release command is input together with the position information of the target analog output module 20 and the input reset release command and the position information are received, the analog output module 20 outputs a control output value when the position information indicates itself. Is released, the reset mode of the desired analog output module 20 can be released online, and labor for going to the site can be omitted.

After the system control is resumed by the on-line operation, the reset state can be recovered while monitoring various kinds of plant state information such as temperature, pressure, and flow rate, and the instrumentation unified signal can be set and operated smoothly and smoothly. Operability and maintainability can be improved.

As the engineering tool 30, by clicking the batch reset release icon 37,
When the batch release command of the reset mode is input, the analog output module 20 receives the batch release command, and when the analog output module 20 controls the control output value to zero,
Since the control to zero is released, the reset state can be immediately released by one key operation when releasing the reset mode of all the analog output modules 20, so that the time until the restart of the normal control is greatly reduced. As well as M
TTR can be shortened.

(Third Embodiment) FIG. 8 is a schematic diagram showing a configuration of an analog output module according to a third embodiment of the present invention. The analog output module 20a is a modified configuration of the first or second embodiment, and is capable of shifting to the above-described output mode when an abnormality of other desired contents occurs in addition to an abnormality of stopping the I / O bus transmission. Has become.

Specifically, the analog output module 20
The control unit 21a in the “a” includes a stop time monitoring unit 23 and a CP that monitors the runaway of the CPU 41 in the control unit 21a.
U runaway monitoring section 42, D / A conversion monitoring section 43 for monitoring abnormality of D / A conversion section 24, transmission error monitoring section 44 for monitoring I / O bus transmission hardware error, and monitoring sections 42-4.
There is a monitor selection storage unit 45 in which selection (; operate) / non-selection (; not operate) of the four are stored. Note that the engineering tool 30 can set selection / non-selection of each of the monitoring units 42 to 44 in the monitoring selection storage unit 45 by an operator's operation in the setting function described above.

Here, the CPU runaway monitoring unit 42
41, a WDT (watchdog timer) monitoring unit 46, and a flip-flop 47. Although the whole CPU 41 is depicted in the CPU runaway monitoring unit 42 in the drawing, the processing of the control unit 21a, the D / A conversion monitoring unit 43, and the transmission error monitoring unit 44 can be executed as appropriate. .

One function of the CPU 41 is to set the D terminal of the flip-flop 47 to "1 (H level)" when the contents of the output mode storage section 22 are in the reset mode, and to set it to "0 (L level)" in the hold mode. Function and WD
W monitor periodically so as not to time up the T monitor 46.
And a function of providing a DT reset signal to the WDT monitoring unit 46.

The WDT monitoring section 46 always counts the time, resets the counted time when receiving the WDT reset signal from the CPU 41, and when the WDT reset signal is interrupted and the time counting result exceeds a predetermined value, the CP counts.
It has a function of giving a U reset signal to the CPU 41 and the CK terminal of the flip-flop 47.

When the flip-flop 47 receives the CPU reset signal from the WDT monitor 46 at the CK terminal,
If the terminal is "0", nothing is performed, and if the terminal D is "1", a reset signal is output from the Q terminal to the OR logic element 25.

The D / A conversion monitor 43 is provided with the D / A converter 2
4 is monitored, and when an abnormality is detected, the output mode storage unit 2
2 is in the reset mode, the reset signal
It has a function of outputting to the R logic element 25.

The transmission error monitoring unit 44 monitors a transmission error of the I / O bus such as a parity error or a reception size over and detects an abnormality, and when the mode identification information of the output mode storage unit 22 indicates the reset mode, , A reset signal to the OR logic element 25.

The monitoring selection storage section 45 stores the monitoring sections 23 and 4
For the items 2 to 44, selection (; operate) / non-selection (; not operate) is set in advance by the engineering tool 30 from the terminal 31.

Next, the operation of the control system configured as described above will be described. First, the engineering tool 30 operates the terminal 31 to operate the monitoring selection storage unit 45.
The operation / non-operation of each of the monitoring units 23, 42 to 44 is set in the table. Specifically, for example, the stop time monitoring unit 23 and the CPU
The case where the runaway monitoring unit 42 is set to “select” and the transmission error monitoring unit 44 and the D / A conversion unit 43 are set to “unselected” will be described. However, since the stop time monitoring unit 23 operates as described above, its description is omitted, and here, the CP
Only the operation of the U runaway monitoring unit 42 will be described.

In the CPU runaway monitoring section 42, the WDT monitoring section 46 monitors the CPU 41 by a well-known WDT method.
That is, the WDT monitoring unit 46 counts up the time, and the CPU 41 periodically sends a WDT reset signal to the WDT monitoring unit 46 so that the WDT monitoring unit 46 does not time up. Normally, from this count up, WDT
The processing up to the reset is repeatedly executed.

Here, if a failure occurs in the CPU 41 or an abnormality occurs in the internal processing, the WDT reset signal is not output, and the WDT monitor 46
The reset signal is output to the flip-flop 47 or the like.

When the flip-flop 47 receives the CPU reset signal from the WDT monitor 46 at the CK terminal,
If the terminal is "0", nothing is performed (hold mode setting). Here, since the D terminal is "1" (reset mode setting), the reset signal is input from the Q terminal to the OR logic element 2.
5 is output.

Thereafter, the OR logic element 25 passes the reset signal to the reset terminal 24r of the D / A converter 24 as described above, and the unified instrumentation signal output from the D / A converter 24 becomes 0 mA. . As a result, it is possible to shift to the reset mode for a preset abnormality. Similarly, when “selection” is set by the engineering tool 30 for the transmission error monitoring unit 44 and the D / A conversion unit 25, the CPU 41 detects a transmission error abnormality and a D
Monitors / A conversion abnormalities. Further, when detecting an abnormality, the CPU 41 outputs a reset signal to the OR logic element 25 only when the content of the output mode storage unit 22 is in the reset mode. Thereby, the analog output module 20
The mode shifts to the reset mode as described above. When the abnormality is detected and the contents of the output mode storage section 22 are in the hold mode, the reset signal is not output and the mode shifts to the hold mode.

As described above, according to the present embodiment, the analog output module 20 includes, for each item relating to abnormality monitoring, a monitoring selection storage unit 45 for storing selection identification information indicating selection or non-selection, When the selection identification information of the corresponding item in the monitor selection storage unit 45 indicates selection, and when a corresponding abnormality is detected and an abnormality is detected, the output mode storage unit 22 is referred to. When the identification information indicates the hold mode, the control output value is held at the value immediately before the abnormality detection, and when the mode identification information indicates the reset mode, the plurality of types of monitoring units 23, 42 to 44 which set the control output value to zero are provided. As the engineering tool 30 has the setting function to set the selection identification information in the monitoring selection storage unit 45, the effect of the applied embodiment is For example, it is possible to select the contents of the abnormality monitoring in accordance with the contents of the control system, at the time of abnormality occurs, the impact on the control system can be kept to a minimum.

(Fourth Embodiment) FIG. 9 is a schematic diagram showing a configuration of an analog output module according to a fourth embodiment of the present invention. The present embodiment is a modified configuration of any of the first to third embodiments. Here, a modified configuration of the third embodiment will be described as an example. (MA / sec) to lower the instrumentation unified signal.

Specifically, the analog output module 20
The OR logic element 25 is omitted, while the engineering tool 30 previously stores the drop characteristic of the unified instrumentation signal at the time of reset, and the reset signal of each monitoring unit 23, 42 to 44. A descent control unit 49 is provided which, when received, gives the output data to the D / A conversion unit 24 while lowering the output data based on the contents of the descent characteristic storage unit 48. The engineering tool 30 can set the descent characteristic at the time of reset in the descent characteristic storage unit 48 by an operator's operation in the setting function described above.

Here, as shown in FIG. 10, the descending characteristic storage unit 48 stores the final arrival value i (4 mA) of the unified instrumentation signal,
The descent characteristic including the descent time t (sec) to the final attainment value is set by the engineering tool 30. The descent characteristic may be any value as long as it can define how the unified instrumentation signal is dropped. For example, a descent gradient (mA / sec) may be used instead of the descent time.

According to the configuration described above, as the analog output module 20, the drop characteristic of the control output value when the control output value is set to zero by each of the monitoring units 23, 42 to 44 is stored. A characteristic storage unit 48 is provided, and as the engineering tool 30, the descent characteristic storage unit 48
Thus, the descent characteristic is set in the descent characteristic storage unit 48, and the descent control unit 49 of the analog output module lowers the control output value according to the descent characteristic in the descent characteristic storage unit 48 when setting the control output value to zero. In addition to the effects of the third embodiment, the method of lowering the control output value at the time of reset can be selected according to the contents of the control system. Therefore, when an abnormality occurs, the control is performed so as to reliably realize the fail-safe operation. A system can be built.

At the time of shifting to the reset mode described above,
Since the descent characteristic control unit 49 gives the output data to the D / A conversion unit 24 according to the descent characteristic in the descent characteristic storage unit 48,
The present invention can be applied to a control valve 8 or a control plant having characteristics that do not want to be set to 0 mA immediately upon reset.

(Other Embodiments) In the second embodiment, the case where the system configuration information does not include the channel number indicating the data path has been described. However, the present invention is not limited to this. Even with the configuration including
The present invention can be implemented in a similar manner to obtain similar effects.

In the second embodiment, the alarm screen 34 and the reset release screen 35 are described as separate screens. However, the present invention is not limited to this. The alarm screen 34 and the reset release icon 36 (the reset batch release icon 37 May be simultaneously displayed, the same effect can be obtained by implementing the present invention in the same manner.

In addition, the present invention can be variously modified and implemented without departing from the gist thereof.

[0097]

As described above, according to the present invention, it is possible to provide an analog output device which can be realized at low cost and which can eliminate the possibility of a large trouble caused by incorrect mounting, and a control system using the same. Further, even during system operation, the specification of the output mode at the time of abnormality can be changed, and operability and workability during maintenance can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of an analog output module applied to a control system according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a partial configuration of a control system according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a mode setting screen in the embodiment.

FIG. 4 is a schematic diagram showing a hardware configuration screen according to the embodiment;

FIG. 5 is a schematic diagram showing an alarm screen in the embodiment.

FIG. 6 is a schematic diagram showing a reset release screen in the embodiment.

FIG. 7 is a schematic diagram showing a reset release screen according to the embodiment;

FIG. 8 is a schematic diagram showing a configuration of an analog output module according to a third embodiment of the present invention.

FIG. 9 is a schematic diagram showing a configuration of an analog output module according to a fourth embodiment of the present invention.

FIG. 10 is a schematic diagram for explaining a drop characteristic in the embodiment.

FIG. 11 is a schematic diagram showing a schematic configuration of a conventional plant control system.

FIG. 12 is a schematic diagram showing a configuration of a conventional analog output module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Operator station 2 ... Control station 3 ... Control LAN 4, 5 ... I / O module 6 ... I / O bus 7 ... Main control device 8 ... Operating valve 9 ... I / O bus transmission part 20, 20a ... Analog output module 21, 21a ... control unit 22 ... output mode storage unit 23 ... stop time monitoring unit 24 ... D / A conversion unit 24 r ... reset terminal 25 ... OR logic element 30 ... engineering tool 31 ... terminal 32 ... mode setting screen 33 ... hardware Configuration screen 34 ... Alarm screen 35 ... Reset release screen 36 ... Reset release icon 37 ... Batch reset release icon 41 ... CPU 42 ... CPU runaway monitoring part 43 ... D / A conversion monitoring part 44 ... Transmission error monitoring part 45 ... Monitoring selection storage Unit 46: WDT monitoring unit 47: flip-flop 48: descent feature The storage unit 49 ... drop the control unit

Claims (8)

[Claims] 1. An analog output device for performing data transmission with a higher-order control device and providing a control output value to a lower-order control object, wherein mode identification information indicating a hold mode or a reset mode is set in advance. Means, when the data transmission is stopped for a predetermined time or more, when the mode identification information indicates a hold mode by referring to the mode storage means, the control output value is held at a value immediately before abnormality detection; An analog output device comprising: a stop abnormality monitoring control unit that sets a control output value to zero when the information indicates a reset mode. 2. The control system using an analog output device according to claim 1, wherein the control device supports creation of a control program and an application program for controlling the analog output device, and the analog output device. A terminal equipped with an engineering tool for transmitting and receiving the control program, the application program and the device configuration information is registered, and the engineering tool stores the mode identification information. A control system comprising a mode setting means for setting the mode in said mode storage means. 3. The control system according to claim 2, wherein the engineering tool includes an analog output device designated by the device configuration information and the analog output device based on the device configuration information and the mode identification information. A control system comprising display processing means for displaying the set mode identification information in association with the set mode identification information. 4. The control system according to claim 3, wherein the analog output device has status transmission means for transmitting its own output status, and the display processing means includes an output status obtained from the status transmission means. A control system for displaying an analog output device designated by the device configuration information in association with the analog output device. 5. The control system according to claim 4, wherein the engineering tool has a release input unit for inputting a reset release command together with position information of a target analog output device, wherein the analog output device is Receiving a reset release command and position information input by the release input means, when the position information indicates the self, a mode release means for releasing the control of the zero value of the control output value. Control system. 6. The control system according to claim 5, wherein the engineering tool has batch release input means for inputting a reset batch release command, and the analog output device receives an input by the batch release input means. A control system, comprising: a batch release unit for releasing the control to zero when the self is controlling the control output value to zero when receiving the batch release command. 7. The control system using the analog output device according to claim 1, wherein the analog output device stores selection identification information indicating selection or non-selection for each item related to abnormality monitoring. Means, provided for each item related to the abnormality monitoring, and when the selection identification information of the corresponding item in the selection information storage means indicates selection, executing the corresponding abnormality monitoring and detecting an abnormality,
Referring to the mode storage means, when the mode identification information indicates the hold mode, the control output value is held at a value immediately before abnormality detection, and when the mode identification information indicates the reset mode, the control output value is set to zero. And a selection setting unit for setting the selection identification information in the selection information storage unit. 8. The control system according to claim 7, wherein the analog output device is configured to store a fall characteristic of the control output value when the control output value is set to zero by the abnormality monitoring control unit. Characteristic storage means; and descent control means for lowering the control output value according to a descent characteristic in the descent characteristic storage means when the control output value is set to zero, wherein the engineering tool comprises: And a descent setting means for setting a descent characteristic.