why the SCAN time of DCS is more & that of PLC is less?
if the SCAN time of DCS then why we use DCS.
Answers were Sorted based on User's Feedback
Answer / bm
Scan time of DCS is more than the scan time of PLC when the
I/O's are digital.
Whereas the scan time of DCS is less than the scan time of
PLC when the I/O's are analog.
Hence DCS is better when analog signals are considered
whereas PLC is better when digital signals are considered.
However DCS do handle both analog and digital signals. It
can also have more no. of I/O's compared to PLC. Hence we
use DCS.
Is This Answer Correct ? | 33 Yes | 7 No |
Answer / kyle condran
DCS are not PC based. the configuration and operating software are but the actual control happens in a control module. DCS usually have a fixed scan time 50ms+, but not always, regardless of I/O count or program size.
PLC scan time depends on Program size and I/O used in the program.
Is This Answer Correct ? | 5 Yes | 0 No |
Answer / solomon
Eventhough PLC scan time is less,DCS is selected for its
I/O availability.About 1 lakh I/O available in DCS.
Is This Answer Correct ? | 11 Yes | 10 No |
DCS is pc based system. The speed of the processor/CPU
decides the scan time.
Is This Answer Correct ? | 3 Yes | 28 No |
What is critcal speed. what is resonant frequency. why we want to cross crtcal speed on higher RPM (early).
What is protocol ?
How INtools is useful for routine Instrument maintenance?
what is loop1 and loop2 in MTS LT?
why we use 24 vdc in instruments mostly?
what is dedband in instrumentation ?
What is cavitation. what is the effect of it on control valve and how is it prevented.
IS IT POSSIBLE TO CALIBRATE A LEVEL TRANSMITTER INDICATOR(ABB) USING HART COMMUNICATOR.? I MEAN TO CHANGE FROM ONE UNIT TO ANOTHER WITHIN INDICATOR (EG. INCH TO FEET)...? PLZ NOTE THAT I HAVE MADE THE UNIT CHANGE IN TRANSMITTER USING HART COMMUNICATOR..BUT WHAT ABOUT THE INDICATOR..?
Why 1-5 vdc a standard?
1 Answers Process Control Technologies,
how will you check torque value during Factory acceptance Test for control valve/ESD ON/OFF VALE how will you confirm this torque value is being correct, Which document will you be refer.
what is the difference between magnetic flow meter and mass flowmeter
what is the difference between SCADA and DCS?