JP2000090016A - Input/output slave bus duplex method for digital control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the input/output slave bus duplex method of a digital control system, which can duplex a slave bus only by means of changing the connection of modules without largely changing the constitution of hardware and can improve reliability. SOLUTION: When main input/output slaves 6 and 8 or a self-slave bus 5A are abnormal, a backup input signal 13b inputted from an input isolator 10 is inputted to a self-controller 4A through a backup input slave 7, the other slave bus 5B, the other controller 4B and a control way 2. An operation based on the backup input signal 13b is executed in a self-controller 4A and an output signal 14 as an operation result is outputted to an output isolator 12 through the control way 2, the other controller 4B, the other slave bus 5B and a backup output slave 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for duplicating an input / output slave bus of a digital control system.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a digital control system used for various controls of a boiler.
The digital control system includes a plurality of (two in the example of FIG. 2) controllers 4 connected in parallel via a control way 2 and having a control circuit 3 therein, in one process control unit 1. , A single slave bus 5 is provided corresponding to each controller 4, and the slave bus 5 has a main input slave 6,
A backup input slave 7, a main output slave 8, and a backup output slave 9 are connected in parallel, an input isolator 10 is connected to the main and backup input slaves 6, 7, and a main and backup output slave is connected. An output isolator 12 is connected to the output isolator 8 and 9 via a duplex switching box 11, and the input isolator 10 is provided with a transmitter (not shown) for pressure, flow rate, temperature, and the like installed at the site. ) Is connected and the input signal 13 from the transmitter is
The output isolator 12 is connected to a control valve (not shown) for controlling pressure, flow rate, temperature, etc., installed at the site. 14 'is output to a control valve or the like.

The controller 4 and the control way 2 are duplexed into a main and a backup similarly to the input slaves 6 and 7 and the output slaves 8 and 9, but FIG. 4
And only control way 2 is shown in FIG.
1 shows the internal structure and connection method of only one controller 4 provided side by side in the process control unit 1, and the other controllers 4
Are omitted from the drawings, but have the same configuration.

In the digital control system as described above, an input signal 13 as a current signal such as a pressure, a flow rate, and a temperature from a transmitter (not shown) on the site is input to the input isolator 10, and the input isolator 10 The main input signal 13a and the backup input signal 13b, which have been converted into voltage signals, have been converted into the voltage signals, respectively.
The main input signal 6 is output to the main input slave 6 and the backup input slave 7, and the main input signal 1 is output between the main input slave 6 and the backup input slave 7.
3a and the backup input signal 13b are A / D
(Analog / digital) conversion and input to the controller 4 via the slave bus 5.

Here, since the main input signal 13a and the backup input signal 13b are converted into voltage signals, there is no problem if both input signals 13a and 13b are input to the controller 4 at the same time.

In the controller 4, when the main input slave 6 is normal, the main input signal 13
Various calculations are performed by the internal control circuit 3 based on a, and an output signal 14 as a calculation result is output from the control circuit 3 to the main output slave 8 and the backup output slave 9 via the slave bus 5. The output signal 14 of each of the main output slave 8 and the backup output slave 9 is D / A (digital / analog).
The output is converted and output to the duplex switching box 11 as the main output signal 14a and the backup output signal 14b. Here, when the main output slave 8 is normal, the main output signal 1 is output by the duplex switching box 11.
4a is selected, the main output signal 14a is output as an output signal 14 'via the output isolator 12 to a pressure, flow rate, temperature, etc. control valve (not shown) or the like installed at the site. The degree of opening is adjusted.

When an abnormality occurs in the main input slave 6, various calculations are performed in the internal control circuit 3 based on the backup input signal 13b, and an abnormality occurs in the main output slave 8. In this case, the backup output signal 14b is selected by the duplex switching box 11, and the backup output signal 14b is output as the output signal 14 'via the output isolator 12 to control valves (eg, pressure, flow rate, temperature, etc.) installed at the site. (Not shown) and the like, the opening degree of the control valve is adjusted, and if an abnormality occurs in the controller 4 or the control way 2, the controller or the control way (not shown) is connected to the backup side. It can be switched.

[0008]

In the digital control system as described above, the controller 4, the control way 2, the input slave 6, and the output slave 8 are duplicated, but the slave bus 5 has a single configuration. Therefore, if the slave bus 5 itself goes down for some reason, the backup of the controller 4, the control way 2, the input slave 6, and the output slave 8 also becomes ineffective, and input / output becomes completely impossible. And has been regarded as a problem in terms of reliability.

Incidentally, duplicating the slave bus 5 in terms of hardware would fundamentally change the entire system, and was extremely difficult to realize.

In view of the above circumstances, the present invention provides a digital control system which can duplicate a slave bus and improve reliability by merely changing the connection between modules without largely changing the hardware configuration. The purpose of the present invention is to provide a method for duplicating an input / output slave bus of a system.

[0011]

According to the present invention, there are provided a plurality of controllers connected in parallel in a same process control unit via a control way, and a single slave bus provided for each controller. And a main input / output slave provided for each controller, a backup input / output slave provided for each controller, and an input / output isolator provided for each controller. A method for duplicating an input / output slave bus of a digital control system, comprising connecting a main input / output slave to a controller via a corresponding own slave bus, and a control way, another controller, and another slave corresponding to the other controller. Connect the backup I / O slave via the bus and An input isolator is connected to the backup input slave, and an output isolator is connected to the main and backup output slaves. When the main input / output slave and its own slave bus are normal, the input signal input from the input isolator is used as the main input slave. And input to the own controller via the own slave bus, perform an operation based on the input signal in the own controller, and output an output signal as an operation result to the output isolator via the own slave bus and the main output slave On the other hand, when the main input / output slave or the own slave bus is abnormal, the input signal input from the input isolator is input to the own controller via the backup input slave, another slave bus, another controller, and the control way, and the own controller is controlled. Performing an operation based on an input signal and outputting an output signal as an operation result to an output isolator through a control way, another controller, another slave bus, and a backup output slave. This is related to a slave bus duplication method.

According to the above means, the following effects can be obtained.

When the main input / output slave and the own slave bus are normal, an input signal input from the input isolator is input to the own controller via the main input slave and the own slave bus, and the own controller uses the input signal based on the input signal. The operation is performed, and an output signal as the operation result is output to the output isolator via the own slave bus and the main output slave.

On the other hand, when a main input / output slave or its own slave bus is abnormal, an input signal input from the input isolator is input to its own controller via a backup input slave, another slave bus, another controller, and a control way. The own controller performs a calculation based on the input signal, and an output signal as a calculation result is output to the output isolator via the control way, another controller, another slave bus, and a backup output slave.

As a result, the slave bus is duplicated, so that even if the own slave bus goes down for some reason, the input / output can be maintained.
The reliability will be greatly improved.

[0016]

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

FIG. 1 shows an example of an embodiment of the present invention. In the figure, portions denoted by the same reference numerals as those in FIG. 2 represent the same components, and the basic configuration is the same as that of the conventional device shown in FIG. The feature of the illustrated example is that, as shown in FIG. 1, one controller 4 (hereinafter referred to as its own controller 4A) is provided with a corresponding slave bus 5 (hereinafter referred to as its own slave bus 5A). ), And the control way 2 and another controller (hereinafter, referred to as another controller 4B) and another slave bus 5 (hereinafter, referred to as the other controller 4B) corresponding to the other controller 4B. The backup input / output slaves 7 and 9 are connected via the other slave bus 5B), the input isolator 10 is connected to the main and backup input slaves 6 and 7, and Via the duplex switch box 11 to the output slave 8,9 of Kkuappu Output Channel 12
In addition, the main input signal 13 input from the input isolator 10 when the main input slave 6 and the own slave bus 5A are normal in the own controller 4A.
is input to the control circuit 3 of the own controller 4A via the main input slave 6 and the own slave bus 5A, while the main input slave 6 or the own slave bus 5A
In the event of an abnormality, the input 13 from the input isolator 10
b is a backup input slave 7 and another slave bus 5
A different point is that a switch 15 is provided for inputting to the control circuit 3 of the own controller 4A via B, the other controller 4B and the control way 2.

Although not shown, the other slave bus 5
B is connected to the main input / output slave of the other controller 4B, and the own slave bus 5A is connected to the backup input / output slave of the other controller 4B.

Next, the operation of the illustrated example will be described.

When the main input / output slaves 6, 8 and the own slave bus 5A are normal, the main input signal 13a input from the input isolator 10 is transmitted to the own controller 4 via the main input slave 6 and the own slave bus 5A.
A, and various operations are performed in the internal control circuit 3 based on the main input signal 13a by switching of the switch 15, and an output signal 14 as an operation result is transmitted from the control circuit 3 to the own slave bus 5A. The output signal 14 is output to the main output slave 8 through the D / A (digital / analog) conversion, and the main output signal 14 a is converted to the duplex switching box 11.
Is output as an output signal 14 'via the output isolator 12 to a control valve (not shown) for controlling pressure, flow rate, temperature, etc., installed at the site, and the opening degree of the control valve is adjusted. .

On the other hand, when the main input / output slave 6, 8 or its own slave bus 5A is abnormal, the input isolator 1
0 is input to the own controller 4A via the backup input slave 7, the other slave bus 5B, the other controller 4B and the control way 2, and the switch 15 switches the backup input signal. 13b, various operations are performed by the internal control circuit 3, and an output signal 14 as a result of the operation is output from the control circuit 3 to the backup output slave 9 via the control way 2, the other controller 4B, and the other slave bus 5B. And the output signal 14 of the backup output slave 9 is D / A
(Digital / Analog) and the backup output signal 14b is
The output signal 14 ′ is output as an output signal 14 ′ via the output isolator 12 to a control valve (not shown) for controlling pressure, flow rate, temperature, etc., and the opening degree of the control valve is adjusted.

As a result, the slave bus 5 is also duplicated like the controller 4, the control way 2, the input slave 6, and the output slave 8, so that
Even if the own slave bus 5A goes down for some reason, the input / output can continue, and the reliability is greatly improved.

As described above, the slave bus 5 can be duplicated by merely changing the connection between the modules without largely changing the hardware configuration, and the reliability can be improved.

The method of duplicating the input / output slave bus of the digital control system according to the present invention is not limited to the above-described example, and various changes can be made without departing from the gist of the present invention. Of course.

[0025]

As described above, according to the input / output slave bus duplication method of the digital control system of the present invention, the slave bus can be changed only by changing the connection between the modules without greatly changing the hardware configuration. Can be duplicated, and an excellent effect that reliability can be improved can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a conventional example.

[Explanation of symbols]

 1 Process control unit 2 Control way 4 Controller 4A Own controller 4B Other controller 5 Slave bus 5A Own slave bus 5B Other slave bus 6 Input slave 7 Input slave 8 Output slave 9 Output slave 10 Input isolator 12 Output isolator 13 Input signal 13a Main input Signal (input signal) 13b Backup input signal (input signal) 14 Output signal 14 'Output signal 14a Main output signal (output signal) 14b Backup output signal (output signal)

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) SS07 TT05

Claims (1)

[Claims] 1. A plurality of controllers connected in parallel within a same process control unit via a control way, a single slave bus provided corresponding to each controller, and a controller corresponding to each controller. An input / output slave of a digital control system comprising a main input / output slave provided, a backup input / output slave provided for each controller, and an input / output isolator provided for each controller. A bus duplexing method, wherein a main input / output slave is connected to an own controller via a corresponding own slave bus, and backup input is performed via a control way, another controller, and another slave bus corresponding to the other controller. Connect the output slaves and use the main and backup input threads. In addition to connecting an input isolator to the main and backup output slaves, an output isolator is connected to the main and backup output slaves. While inputting to the own controller via the bus, performing an operation based on the input signal in the own controller, and outputting an output signal as an operation result to the output isolator via the own slave bus and the main output slave, When the input / output slave or its own slave bus is abnormal, the input signal input from the input isolator is input to its own controller via the backup input slave, another slave bus, another controller, and the control way, and the input signal is input to the own controller. Based on Performs the operation, input and output slave bus duplexing method for a digital control system and outputs an output signal as the operation result via the output slave control way and the other controllers and other slave bus and a backup to an output isolator.