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Is there a way to review the Digital Input/Digital Output LED light history of a Siemens S7-1200 PLC?

If so, is it through the web portal or through Simatic and can someone point me in the direction of where to find such information?

Thanks - will save me a site visit if possible in any way.

ZF007
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Emko
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  • Im fairly sure there is not anything built into Simatic directly. Did you check if the PLC tags are recorded in a historian database? For future troubleshooting if you want to record PLC tags you could use something like plc analyzer – A Murray Jul 18 '15 at 13:18
  • It is not possible. Because it doesn't make any sense. IO LEDS are indicating the bit value that has been send to the input or ouput. These values can be stored in an archive indeed. The status LEDs on the CPU can be read. The history of these LEDs are stored in the diagnostic buffer. –  Jul 25 '15 at 15:36

1 Answers1

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There is no built in DI/DQ history for the S7-1200.

However, if you have some form of TCP/IP connection, this can be done quite easily.

When you call outputs in your main program, use a tag based calling system. Reference that tag, and have the tag's output be:

  1. The required DQ
  2. A TCP/IP message saying that this tag has risen or fallen.

For inputs, just send a message on the rise and fall of each input

It is likely easiest to hold this DI/DQ history on the server that is hosting this TCP/IP connection rather than the PLC itself.

Quinn Turner
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