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STEP 7 / STEP 7 Lite

Reading Pulses Problem

Thread Starter: David.D Started: 7/27/2012 2:37 AM Replies: 1

7/27/2012, 2:37 AM

David.D

Joined 7/27/2012

Last visit: 7/31/2012

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Hi everyone,

I am new to this forum. I am using the ET200S of the PLC. I am having a problem counting correctly the number of pulses that I am receiving through an input. I have tried using the PLC's input pulses to test the outcome but I am not receiving the same number of pulses as I should be getting. For example, in one minute, I am suppose to get 60 puleses if I send a pulse of 1 per/sec. I am checking for falling and raising edges but one input or pulse increased a count variable that I have placed on the output by more than 10. I did however used a counter to get the correct counts but then I am measuring the count increases at 10 per/sec. The faster the pulse, the higher the error increases. It is like the PLC is not reading correctly the number of pulses. Have anyone incountered this? Any fix at all would help please?

Thanks,
Dav D.

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7/31/2012, 2:45 PM

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