Processing method for preventing instructions from returning to zero after control unit is restarted in thermal-control DCS

Abstract

The invention discloses a processing method for preventing instructions from returning to zero after a control unit is restarted in a thermal-control DCS. On the original configuration logical basis,a selector and / or a door logical device are introduced, an operator is controlled by initialized state signals of a control unit to enter the tracking state, control instructions output by the operator are equal to position feedback signals of controlled equipment, it is avoided that the control instructions return to zero after the control unit is initialized, and safe running of a unit is influenced, and the original function of a system is reserved. According to the processing method, by introducing a number-setting device, a non-gate logic device, a timer, a comparator and a gate logic device, three methods for obtaining the initialized state signals of the control unit are provided.

Description

technical field

[0001] The invention relates to a method based on DCS system application software configuration technology, which is mainly used in the fields of thermal control of power plants and the like. Background technique

[0002] In the DCS system of the generator set, the control unit issues control commands according to the control configuration, and outputs them through the AO card (usually 4-20mA control signal) to control the controlled equipment on site. When the position feedback signal of the controlled device (referred to as valve position) is equal to the control command, the controlled device enters a static state and keeps its position unchanged. At this time, the command and feedback balance, and the controlled device is at the controlled target position.

[0003] The DCS control system of the generator set is usually configured with dual distributed control units, also known as dual DPUs, and the main control DPU and the auxiliary control DPU are hot st...

Examples

Embodiment 1

[0042] Embodiment 1 (method 1):

[0043] In this embodiment, the initialization status signal of the control unit is obtained by the following method: a counter and a timer are set in the configuration, and after the initialization of the control unit is completed, the timer is driven by the counter to count, and the timer output is initialized The state signal is used to connect the output end of the timer with the selection control end of the selector and the second input end of the OR gate logic device respectively.

[0044] After the control unit is initialized and works normally, each functional module in the configuration starts to work. At this time, the output state of the register automatically changes to the preset logic state. Specifically, such as figure 2 , the register can be set to "0" or "1" after the initialization of the control unit through parameter setting in advance. If it is set that the counter is set to "0" after the initialization of the control un...

Embodiment 2

[0049] Embodiment two (method two):

[0050] In this embodiment, the initialization status signal of the control unit is obtained by the following method: judging whether the control unit is initialized by judging whether a number of analog control commands in the control unit return to zero at the same time.

[0051] Specifically, such as image 3 , select a number of analog control signal terminals of the control unit, set a number of comparators corresponding to the analog control signal terminals in the configuration, and compare the analog control signal terminals with the input terminals of the corresponding comparators connected, the comparator is used to compare the analog control signal with zero, if the analog control signal returns to zero then output 1; the AND gate logic device is set, and the output terminals of each comparator are respectively connected with the AND gate logic device The input end is connected; Timer is set, and the output end of gate logic dev...

Embodiment 3

[0054] Embodiment three (method three):

[0055] The initialization status signal of the control unit is obtained by the following methods: as Figure 4 , set the first comparator, the second comparator and the AND gate logic in the configuration;

[0056] The first input terminal of the first comparator is used to input the position feedback signal of the controlled device, the second input terminal of the first comparator is connected with the output terminal of the manipulator, and the output terminal of the first comparator is connected with the Connected with the first input terminal of the gate logic; the first comparator is used to judge whether the difference between the position feedback signal of the controlled device and the control command output by the operator is greater than the preset threshold, if it is greater than the preset threshold Then the output terminal outputs "1", otherwise it outputs "0". The threshold needs to be determined according to the actua...

technical field

[0001] The invention relates to a method based on DCS system application software configuration technology, which is mainly used in the fields of thermal control of power plants and the like. Background technique

[0002] In the DCS system of the generator set, the control unit issues control commands according to the control configuration, and outputs them through the AO card (usually 4-20mA control signal) to control the controlled equipment on site. When the position feedback signal of the controlled device (referred to as valve position) is equal to the control command, the controlled device enters a static state and keeps its position unchanged. At this time, the command and feedback balance, and the controlled device is at the controlled target position.

[0003] The DCS control system of the generator set is usually configured with dual distributed control units, also known as dual DPUs, and the main control DPU and the auxiliary control DPU are hot st...

Examples

Embodiment 1

[0042] Embodiment 1 (method 1):

[0043] In this embodiment, the initialization status signal of the control unit is obtained by the following method: a counter and a timer are set in the configuration, and after the initialization of the control unit is completed, the timer is driven by the counter to count, and the timer output is initialized The state signal is used to connect the output end of the timer with the selection control end of the selector and the second input end of the OR gate logic device respectively.

[0044] After the control unit is initialized and works normally, each functional module in the configuration starts to work. At this time, the output state of the register automatically changes to the preset logic state. Specifically, such as figure 2 , the register can be set to "0" or "1" after the initialization of the control unit through parameter setting in advance. If it is set that the counter is set to "0" after the initialization of the control un...

Embodiment 2

[0049] Embodiment two (method two):

[0050] In this embodiment, the initialization status signal of the control unit is obtained by the following method: judging whether the control unit is initialized by judging whether a number of analog control commands in the control unit return to zero at the same time.

[0051] Specifically, such as image 3 , select a number of analog control signal terminals of the control unit, set a number of comparators corresponding to the analog control signal terminals in the configuration, and compare the analog control signal terminals with the input terminals of the corresponding comparators connected, the comparator is used to compare the analog control signal with zero, if the analog control signal returns to zero then output 1; the AND gate logic device is set, and the output terminals of each comparator are respectively connected with the AND gate logic device The input end is connected; Timer is set, and the output end of gate logic dev...

Embodiment 3

[0054] Embodiment three (method three):

[0055] The initialization status signal of the control unit is obtained by the following methods: as Figure 4 , set the first comparator, the second comparator and the AND gate logic in the configuration;

[0056] The first input terminal of the first comparator is used to input the position feedback signal of the controlled device, the second input terminal of the first comparator is connected with the output terminal of the manipulator, and the output terminal of the first comparator is connected with the Connected with the first input terminal of the gate logic; the first comparator is used to judge whether the difference between the position feedback signal of the controlled device and the control command output by the operator is greater than the preset threshold, if it is greater than the preset threshold Then the output terminal outputs "1", otherwise it outputs "0". The threshold needs to be determined according to the actua...

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