We do have a problem in the company that is one PT connected to PlC which is mean 1 out of 1 in PLC system we do have the PAHH is 55 mbar and PALL 8 mbar with a timer of 15 sec for the PAHH the problem started when PAHH goes more than the set point which is 55 it reached up to 71 but due to timer doesn't trip . We force it and we checked everything nothing there . We replaced the transmitter problem still there the reading goes more than the 55 bar the range for transmitte is 0- 60 mbar . So we did loop check , aculaizing valve , wiring all are okay . What the possible causes for this ???
- 2 Answers
- 4342 Views
- National Petrochemical Company, I also Faced
- E-Mail Answers
Answer Posted / carl ellis
Although the post has lots of information, it isn't clear
exactly what the problem is.
I think the problem is that the PLC does not alarm when the
pressure exceeds (goes above) 55mbar. But I'm not sure.
Given this description: when PAHH (pressure alarm High High)
goes more than the set point which is 55 it reached up to 71
but due to timer doesn't trip . We force it and we checked
everything nothing there, let's suppose that the PLC is not
indicating an alarm state.
a) what should the PLC do at the alarm condition?
b) How is an alarm indicated? A digital output (DO) goes
high? A lamp is driven by a DO lights up?
c) What exactly does not work as it should?
If the PLC does not indicate an alarm, yet the indicated
pressure goes higher than a high alarm, the problem is NOT
the field transmitter, the problem is in the alarm setup or
alarm annunciation.
Troubleshooting depends on
- an explanation of exactly what should be happening
- an explanation of how you know it is not working; that is,
what the evidence is that it is not working.
Yes, the pressure went above 55mbar.
How do you know that?
The transmitter's local display?
A milliampmeter in the analog input circuit?
Did the alarm ever work? Or is this a new commissioning and
you're trying to get the alarm to work?
Carl Ellis
Measure First
| Is This Answer Correct ? | 1 Yes | 0 No |
Post New Answer View All Answers
How to calculate P,I&D value in PID controller ?
How will you test a transistor with a multimeter?
What is eddy current? Describe the operating principle of proximity probe.
what are the diff. in servo and regulatory control?
Explain PID controller tuning & any one method used for it.
How many interlocks at turbine side?
basic connection and principle of axial shift sensor n differential sensors in tubine describes n draw......
How many are the types of instrument cables in terms of No. of pair.
We are using Rosemount 5400 series Radar Level Transmitters in all types of Sump Applications having oily water hdrocarbon petrochemical nature. What we are facing the problem frequently is that always getting reading frezzed at some value. If we do power recycling , sometimes it is working . then making same freezing problem. If anybody faced before such type of problem and also having solution , Please give the answer.
what is dc moter.
what is isloted barrier how it works and what are the main purpose.how it make safe area.
KAlman filter code for two dimension?
pls give me presant awerness quistion and answer in my emailid.
Can any one tell me what type of question asked for instrumentation and control interview panel??? pls mail ramashankar.goel@gmail.com
How to calibrate capillary type level transmitter
