Scan time

[Robert Taruwona]

Today, the difference between PLCs and DCSs is becoming blurred. However, historically PLCs handled the bulk of digital inputs and outputs and the CPU scan time depends on the number of I/Os and the processing power. How do today's DCSs compare with PLCs in terms of the scan time given the same number of inputs and outputs both digital and analog?

 

[Bakerman]

There's processing time, and I/O scan/update time. Today, the I/O update time is usually the same, but the PLC scan time is still much much much faster.