Quick Question about pulse outputs

Sevenfins

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• Mar 13, 2020

• #1

How do I measure if I am getting a signal out of the plc output? All of the outputs are giving me the same voltage, however I am certain that not all of them work.

 

CommissioningMan

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• Mar 13, 2020

• #2

Use a scope if you have one.

 

bernie_carlton

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• Mar 13, 2020

• #3

I think that you will have to describe the situation better. Is the measured value of the output what you expect? If it is how do determine that an output isn't working?

 

Sevenfins

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• Mar 13, 2020

• #4

Okay, so what I am doing here is pulsing an output to a stepper motor. I am using 4 of them. 2 of them work, the other 2 I believe to not be working on their certain outputs due to a surge we had, because they /were/ working, now they are not. The company I work for doesn't have an oscope, that was my first thought.

 

BryanG

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• Mar 13, 2020

• #5

Do you have a spare input on the PLC that you can use as a high speed input? If so you can program it and check the number of pulses received per second. Then try each output to the input in turn. Or if you can program the outputs to change very slowly then you should be able to see them on a multimeter.

 

kallileo

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• Mar 13, 2020

• #6

You don't need a oscilloscope.
Most "not very cheap" multimeters can measure frequency and duty cycle.
The maximum frequency depends on the brand and price.

https://www.amazon.com/Mastech-MS8268-Digital-Manual-Multimeter/dp/B000JQ4O2U

 

Last edited: Mar 13, 2020

drbitboy

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• Mar 14, 2020

• #7

Sevenfins said:

Okay, so what I am doing here is pulsing an output to a stepper motor. I am using 4 of them. 2 of them work, the other 2 I believe to not be working on their certain outputs due to a surge we had, because they /were/ working, now they are not. The company I work for doesn't have an oscope, that was my first thought.

Click to expand...

There are smartphone apps that use the audio microphone as a digital oscope probe; the input wiring would needs a voltage divider, but it's a cheap way to see up to a few kHz.