I/O scanning time for DCS

[sulaa1]

dear all

is there any standard regarding I/O scanning rate for Distributed control system (DCS)

I am trying to look for is there any written standard such ISA,IEC or others

Here my problem,
there is scanning option for all the I/O analog and digital.
there is 250 ms 500ms and 1 sec.

the argument is if I put all in 250ms I/O scanning time the CPU loading is very high but when choose 1 sec the CPU loading is lowered.
if there is any standard please let me know, that will help me on the argument.

 

[IRstuff]

Shouldn't the sampling rate depend on what you need, i.e., what are you trying to get out of the data?

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[sulaa1]

It is I/O processing in DCS, all the analog input and output.
I guess there is a standard on the scanning rate of the I/O.

I do hope some can help if there is standard or not.

 

[IRstuff]

Again, what does your process need? Why are you forcing the sampling rate to be so high? What did your process have before you installed the DCS

TTFN
I can do absolutely anything. I'm an expert!
homework forum: //

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faq731-376 forum1529