What is DCS and PLC scanning time?

Answer Posted / abhishek

Main difference between DCS and PLC is about the scanning
time. PLC's have a fixed scanning time whereas DCS
execuation order(scanning) can be varied with certain
minimum limit. Generally a PLC can have a scan rate of as
low as 5msec(fixed) to some where around 20msec(fixed). As
DCS handles larger number of inputs/outputs its scanning
rate is 50msec and this value needs to be defined (can be
kept more than 50msec) while writing a program. But latest
DCS can have scanning rate of 20msec.

Is This Answer Correct ?    7 Yes 2 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

why fuse block is not used for AI signal?

1400


Regarding , there is an air cooler which control the fans(50% of AV FANS) by temperature in outlet , and the louver of Air cooler is controlled by HIC from control system , So if on Air cooler we will consider 2 individual I/P converter or positioner?

1367


Which is the best field foundation bus. ( FF ) Yokogawa, Honeywell or others ?

1353


how works encoder in plc

1589


HOW TO SOLVE PROBLEM WITH ENRAF LEVEL TRANSMITTER 854 ATG THAT PASSWARD DO NOT Exist INTO TRANSMITTER TO ADJUST LEVEL WITH PORTABLE PET 847, WRITTEN WRONG PASSWORD , I AM SURE THAT DEFAULT PASSWARD (W2=ENRAF2) IS THIS TRANSMITTER NEED TO REPLACE SOFTWARE AND HOW?

2985






How would you choose differential range?

710


What is stripper & spilitter ? Diffrence in this.?

2067


What is zone,loop/fire alarm system?

2081


Please asked me How calculate DCS controller memory.

2344


why we use cascade control and feed foreword control in 3 element control of boiler drum ?what is feed forward and cascade control system ?

1757


Why we are using reverse action in displacer types level transmitters on some Vessels?

2035


how to calibrate load cell

2319


control panel design guidelines

2860


Explain bernoulli’s theorem. State its application.

685


How to calibrate smoke Dectector

1131