Hi everyone.

Is it possible to put a line monitoring on the marshaling cabinet?

As my current knowledge, using end of line resistor for line monitoring, it should be at the end of the line that you want to monitor.

Now, I heard from someone that it is possible to put before the line you want to monitor? What and how is that should be?

 

If you are going to monitor the wiring all the way out to the field contacts, the resistor must be placed at the field contacts. If you put it in the marshaling cabinet you are only monitoring the wiring between the control I/O and the marshaling cabinet.

 

Hi there,

I have the same understanding with you. I really don't know why our consultant insisting that to put on the marshaling.

 

Dear My friends

I needs your help to make connection between SPM relay (Synchronous protection relay) made by GE

I try by using Rs232 to RS485 convector type AIC Allen Bradly but I didn't Succeed

please help me with this matter

 

Hi there,

By installing a extra resistor in parallel (between the supply and return line) in the MCC you will still get a line resistance if the line breaks in the field instead of a "open circuit" error. The MCC resistance can then be used to indicate a definite line breakage somewhere on the field side.

0 ohms can then be used to indicate a definite power failure on the loop. The resistor in series with the field contact and the ELR over both the contact resistor and the contact is still installed in the field switch box.

So normal condition will be the MCC resistor plus the ELR. Switch active will be MCC resistor plus contact resistor plus ELR. Line breakage will only be MCC resistor. Power failure on the loop will be 0 Ohms.