Omnibearing analyzing and solving method for jump problem of contactor

Abstract

The invention provides a method for comprehensively analyzing and solving the jump problem of a contactor. The method specifically comprises the following steps: S1, changing a coil type motor starting control command in an original PLC program into an RS trigger while adding a counting function when motor operation feedback is 1, and when motor operation feedback signals are continuously overturned, setting output to be 0, so that a contactor is released and is not attracted any more; and S2, replacing a starting intermediate relay with a time delay relay, and replacing an original normally open contact with a time delay normally open contact, wherein a contact for feeding back the operation of the motor to the PLC is changed from a normally open contact for starting the intermediate relay to an auxiliary normally open contact of the main contactor, so that the jumping phenomenon caused by the fact that the PLC cannot confirm the actual state of the field due to the fault of the relay or the action time difference between the relay and the main contactor can be effectively avoided. The method has the beneficial effects that the contactor jumping phenomenon caused by voltage fluctuation and software and hardware faults in PLC control is thoroughly eliminated.

Description

technical field

[0001] The invention relates to a control method for electrical equipment, in particular to an all-round analysis and solution method for the jumping problem of a contactor in an electrical control system with PLC. Background technique

[0002] In the main drive electrical control system on large-scale continuous production lines such as hot-rolled strip steel, there are generally electrical and electronic equipment such as main contactors, control relays, PLC controllers, and remote I / O, which are used for rough rolling and finish rolling on the production line. The main drive motors such as coiling and coiling provide operation control means for starting and stopping. However, in the process of actual production and operation, due to the insufficiency of field equipment structure and program design and the voltage fluctuation of the upper power grid, sometimes the main contactor will jump, which is very harmful. Such an accident occurred in the control sys...

Examples

Embodiment Construction

[0020] The comprehensive analysis and solution method for the contactor anti-jumping problem of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0021] Such as figure 1 As shown, it is a schematic diagram of overlapping curves between the program scanning period and the motor operation reverse sequence in the present invention.

[0022] From figure 1 It can be seen from the figure that if the scan period in the on-site PLC program is set to 200MS, when the start signal comes, the motor running feedback signal is transmitted to the PLC by the normally open contact of the relay. There will be a delay closure. When the delay time is greater than 200MS and less than 300MS, the feedback signal received by the PLC will be delayed and turned into "1" at the same time, as shown in Figure ①, and the output of the PLC will be turned from "1" to "0" state output . When the next scan cycle comes, although the relay receive...

technical field

[0001] The invention relates to a control method for electrical equipment, in particular to an all-round analysis and solution method for the jumping problem of a contactor in an electrical control system with PLC. Background technique

[0002] In the main drive electrical control system on large-scale continuous production lines such as hot-rolled strip steel, there are generally electrical and electronic equipment such as main contactors, control relays, PLC controllers, and remote I / O, which are used for rough rolling and finish rolling on the production line. The main drive motors such as coiling and coiling provide operation control means for starting and stopping. However, in the process of actual production and operation, due to the insufficiency of field equipment structure and program design and the voltage fluctuation of the upper power grid, sometimes the main contactor will jump, which is very harmful. Such an accident occurred in the control sys...

Examples

Embodiment Construction

[0020] The comprehensive analysis and solution method for the contactor anti-jumping problem of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0021] Such as figure 1 As shown, it is a schematic diagram of overlapping curves between the program scanning period and the motor operation reverse sequence in the present invention.

[0022] From figure 1 It can be seen from the figure that if the scan period in the on-site PLC program is set to 200MS, when the start signal comes, the motor running feedback signal is transmitted to the PLC by the normally open contact of the relay. There will be a delay closure. When the delay time is greater than 200MS and less than 300MS, the feedback signal received by the PLC will be delayed and turned into "1" at the same time, as shown in Figure ①, and the output of the PLC will be turned from "1" to "0" state output . When the next scan cycle comes, although the relay receive...

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