What is the SCAN time of a DCS/PLC? What is the typical
value for scan time of DCS and PLC?
Answers were Sorted based on User's Feedback
Answer / vicki
scan time is the time taken by DCS/PLC to read inputs,
execute program and as per input/logic update outputs
accordingly. PLC scan time depends on no. of inputs,
outputs and program size(total memory used, heap size). so
it may be different for different program(PLC). less scan
time means faster PLC action. scan time is mostly in mili
seconds, from 2ms onwords.
| Is This Answer Correct ? | 78 Yes | 3 No |
Answer / mohamed yousuf
scan time means the time required to read the
inputs,execute the program and generate the output this is
called scan time the scan time is usually in milli seconds
to nano seconds
| Is This Answer Correct ? | 38 Yes | 3 No |
Answer / amit patel
SCAN time of DCS /PLC defines as execution of one cycle of
program (reads the inputs, executed whole program and
writes output)
Normaly DCS scan time are 200msec ,500msec,1 sec
PLC scan time are less than 100msec.
| Is This Answer Correct ? | 21 Yes | 6 No |
Answer / purushotham
scan time , name it self indicates time required to scan the process of operation.
time taken to finish operation (reading inputs,logic(process) and execution (output) of results).
| Is This Answer Correct ? | 11 Yes | 2 No |
Scan time is the time required to scan the inputs,program written and display the output accordingly.
As scan time of PLC is smaller than that of DCS,we use PLCs for faster operations in Industries.
Normally,PLC are used for Safety Purpose,the switches in interlocks for tripping,etc
| Is This Answer Correct ? | 4 Yes | 0 No |
Answer / sivabalan
PLC/DCS
Scan time is scan input and update input table, then perform logic and update logic table and finally update physical output devices. Taking time to execute above process is called.
Process
Scan input, Perform logic, Update output and finally perform house keeping task such as update the display.
| Is This Answer Correct ? | 1 Yes | 1 No |
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