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Question:

Why the relay output type plc can not control the stepper motor

I use the Mitsubishi plc, is the relay output type, I would like to know why the relay output type can not control the stepper motor. In addition to plc can not send high-speed pulse, there are other reasons? Please help me solve it. If I can not control the output of low-speed pulse? I can now achieve the forward but can not be reversed, my plc output voltage 24V, I would like to be able to achieve reverse ah?

Answer:

Relay metal contacts will occur when the mechanical jitter, a pulse into an uncertain number of different lengths of the pulse
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Not absolutely uncontrollable Can only say that the need for high-speed pulse position control when the relay output PLC can not Analog speed control or communication control (need to support 485 protocol stepper motor amplifier) can also This mainly depends on your specific requirements and control objects The so-called low-speed pulse output of the relay is not impossible, but the speed and accuracy will be very low, the service life will be affected, there is no practical significance
Relay output of the electric shock life of the majority of 200,000 times, you can count, control the motor first from the output speed, the number of times, the control motor one day estimate to use hundreds of thousands of pulses, then the relay The output point is scrapped. High-speed pulse, then the relay output point is certainly no response. So the pulse output will not use the relay output type. Recommendation: with the transistor output type, and it is best not to use the PLC output point directly output, to the transistor output point after a solid state relay, solid state relay and then load. Because the transistor output, then the maximum current is only about 0.6A, if the load is large, it is likely to burn the output point. Solid state relay is different from the general relay, not electromagnetic, is the electronic circuit, can output high-speed pulse.

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