analog signal create problem

rushikesh794

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Join Date
Aug 2016
Location
andhra pradesh
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3
hi all. i using abb ai531 module. when i giving directly 4-20ma plc/module reading is good. but when i giving signal through masibus signal isolator then it taking only few seconds afterwords it disconnect(led in signal isolator is off) automatically.but module/plc reading is shown +32767(a short circuit value).please help for my problem.
by
hrushikesh
 
Test 1:
i using abb ai531 module. when i giving directly 4-20ma plc/module reading is good.

ABB module is OK.

Test 2:
when i giving signal through masibus signal isolator then... module/plc reading is shown +32767

Repeat the test 1. If the module is still OK, you can have a problem with the isolator or with the signal connected to the isolator's input.

Try this:

a) Check the current in the output of the Masibus isolator with a tester.
b) Check if all the wiring is correct.
c) If you have other insolator, you can substitute the suspected one.

I have no access to the isolator's manual so I can't tell for sure if you can use it with the ABB module.
 
If the 4-20mA signal works OK when directly connected to the analog input, why do you need a signal isolator?

If the Isolator is not working, it is either a wiring issue (some are loop powered, some are DC powered, it all depends) or it could be an isolator that did its job after a near lightning strike and died in the line of duty protecting the analog input.
 
hi, when we use multimeter in series the signal is going good to plc/module with signal isolator. but in my application we want to divide one analog signal in to two so we using signal isolator.
another signal from signal isolator is given to indicator its working perfectly
In our same dual project we using ai561 it working perfectly. please help me its urgent we wont hake spare analog output module.
 
a) Can you swap the outputs of the isolator? Just to see if the wrong lecture remains in the same place.

b) Do you have any spare input channel in the PLC? (of course, you'll need to set that channel).
 

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