Author Topic: Wrong data returned from PLC  (Read 1202 times)

cls

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Wrong data returned from PLC
« on: March 18, 2016, 03:31:53 AM »
Hi

I'm logging som values from several PLC's (some numeric values and BIT-values).

I have had som problems lately (3.99d) with wrong values returned from the PLC. This only happens rarely, but the values returned from the PLC is suddenly "old" data and then things are back to normal (eg. number is 10, number is 15, number is 10, number is 17).

I use the EthernetIPforSLCMicroCom driver.

I can re-create the problem, by creating a new project and placing a datasubscriber on the form. Start the logging of values for some time (eg. 1 minute), unplug the network cable from the PLC og then sometimes the logging stil returns values (often it just generates runtime-errors as it should). These values also changes between old values read from the PLC (when the network cable was not unplugged). This doesn't happen every time I unplug the network cable, but if I do a couple of times, it will happen.

I have tried with a timer and read-commands instead of a datasubscriber, and the same thing happens.

Best regards
Claus S.

cls

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Re: Wrong data returned from PLC
« Reply #1 on: April 20, 2016, 04:23:31 AM »
I found a solution, just check the errormessage property of the datasubscriber, if this is not blank, then ignore the data returned.

Claus S.