Batch reactor-Temparature tansmitter loading

Hi guys,
     Our batch reactor in process lab has duplex type RTD.It placed at bottom side of reactor.Here is the problem reagrding same RTD and Transmitter while checking its loop From DCS to field.
 Problem is:

•   Reactor temperature control module showing BAD device indication.It means either device is not connected or its not working

 While searching the root cause of problem we did following steps :

• Started with RTD checking.Measured resistance between 3 Terminal RTD and found it is ok at room temparature.
• Next we checked voltage comming from DCS to tansmitter.As it is duplex RTD we got 11.5 V and 13 V at both transmitter.so we decided to check the loop.
• Firstly in process lab upper junction box we checked cable continuity and we found it ok.Cable tag number 25/Ax AI/41 n so on...so from this we can esily found the same cable in DCS lab and for cross checking checked its continuity in JB.
• We found 24 V coming from DCS by rmoving cable from field instrument but when we were connecting same cable to transmteer voltage drop had occured so the module is showing device is not connected or failure as 24V loop is not completed.
• Now we are checking Transmitter ,so we can make conclusion why voltage drop occuring may be its because of transmitter load.

Just do the same steps when your checking loops in plant.These small things lead you good Instrumentation and control engineer.

take care........
     







     

Batch reactor

Hello....after a long break of our practical work because of  our exams n presentations we were unable to post the recent interesting happenings in our batch reactor pilot plant....

     Its not the meaning that we were not working on that..We worked on interesting concept of  looping .I am saying interesting as it was done previously by the pilot plant developers.After some days the inlet valves are not working.

     We found relay number 12 also not working....so we traced whole loop and finally found one bug in card channel which itself not producing 24 v DC.Now we changed card number and channel number.Now as relay number 12 is working he Inlet valve center one is working now.

     Second problem i found when whole loop is ok but simple fuse in Marshalling cabinet is not working means just blown. we replaced it and checked ,the valve is working now.

      U might think its a just routine maintenance problem but in our opinion if we are able to find those problems and we solve it then it clears our ideas of field instrumentation specifically...I already posted diagram of this batch reactor so you can check which valves were not working(inlet valves).

  Relay card picture also posted in previous blog..

    

Thanks to all...