resolution/scan times
resolution/scan times
(OP)
Can someone briefly define resolution from the standpoint of an analog module? Also, is resolution a function of the processors scan time?
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RE: resolution/scan times
David Baird
mrbaird@hotmail.com
Sr Controls Engineer
EET degree.
Journeyman Electrician.
RE: resolution/scan times
RE: resolution/scan times
Assuming the module has a fixed resolution mean you have the value of your analog input stored in the module at this resolution.
The scan time is the time needed for the processor to read inputs, serve ports, execute the program and write the output.
Updating the analog value in the CPU has two main methods: (assume that you have one module with 8 inputs)
1- the CPU would update the 8 inputs each scan
2- the CPU would update only one input at each scan, so it will take 8 consecutive scans to update all inputs.
The draw back of the first one is the CPU would take considerable time to update all inputs hence the scan time will increase. The second method draw back is each channel would be updated every 8 scans.
Generally there is no connection between scan time and resolution