Does anybody know how to specify the input scan time for Modicon PLCs, specifically Quantum series? Can i set up input point filter time individually or must be in group?

Thanks for any suggestion.

 

There are two issues here:
1. How fast does a particular I/O resolve its IO.
2. How fast does the CPU scan the logic.

Typically you will see (except for High speed counter or independent logic solve devices) that the CPU scan time is typically longer than the IO resolve time.

For the Quantum series PLCs this information is in the manuals contained on:
http://eclipse.modicon.com

Frank Prendergast

 

I'm looking for similar information. I can't find any information in the Modicon docs concerning IO processing/update in relation to logic solving.
Does anyone know where to find specific info on the execution cycle of these controllers?

 

You can use FREERUN function.

 

Thanks for the reply. I understand that IO scan time is faster than CPU logic solve time. But I am looking for the way to define/specify in Modicon IO module scan time. How can I slow down the input scan time?

 

Thanks for the reply. But can you be more specific,what is FREERUN and how the Freerun work?

 

The first operator in project:
T2 := T1;
T1 := FREERUN ();
TIMESCAN = T1 - T2;
INPUTSCANTIME = T1 - T3;

The last operator in project:
T3 := FREERUN ();
LOGICSOLVETIME := T3 - T1;

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