Interposing Relay Panel (IRP)
Check the locations of the components like relay’s and Terminal blocks in the IRP panel shall be as per the approved IRP GA/IA drawing. Refer to the above photograph for easy understanding.
Also Read: What Is Interposing Relay in a PLC?
Termination of Digital Input (DI) signals
- Identify the terminal block for the DI signal as per Instrument wiring interconnection drawing and Electrical schematic wiring drawing.
- Check the cross-wiring between the Electrical side MCC terminal and the System side Instrument terminal.
- Check the proper ferrule for the input signal i.e. Status, L/R, and Fault from and to assigned terminals.
Testing of the Digital input (DI) Signals
- Identify the terminal block for the DI signal as per Instrument wiring interconnection drawing and Electrical schematic wiring drawing.
- Short the terminal blocks of the DI signal at the MCC end in the IRP cabinet.
- Check and ensure the continuity in the multimeter at the terminal end in the IRP cabinet for the same.
- Repeat the above steps for each DI signal and highlight each signal in the I/O list to ensure all the DI signals are covered under the test.
Termination of Digital Output (DO) Signals
- Identify the terminal block and relay numbering for the DO signal as per Instrument wiring interconnection drawing and Electrical schematic wiring drawing.
- Check the cross-wiring between the Electrical side MCC terminal, Relay, and the System side Instrument terminal.
- Check the proper ferrule for the output signal i.e. Start, Stop, and Trip from and to assigned terminals.
Testing of Digital Output (DO) Signals
- Identify the terminal block and relay numbering for the DO signal as per Instrument wiring interconnection drawing and Electrical schematic wiring drawing.
- Inject 24V DC with current ranging from (50-100mA) to the Coil side of the DO signal.
- Confirm that the intended relay is energized / de-energized as per the Electrical schematic wiring drawing.
- Check and ensure the continuity at the MCC end for the same signal using a multimeter.
- Repeat the above steps for each DO signal and highlight each signal in the I/O list to ensure all the DO signals are covered under the test.
Note: Hope the above explanation for the wiring and testing of the Interposing relay panel is understood.
Have a nice day!!
Stay Safe!!
Author: Mohammed Khaleel
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Please can you explain freewheeling diode for inductance