13.60
SEL-311C Relay Instruction Manual Date Code 20060320
Testing and Troubleshooting
Relay Troubleshooting
Relay Troubleshooting
Inspection Procedure
Complete the following procedure before disturbing the relay. After you finish
the inspection, proceed to Table 13.11.
Step 1. Measure and record the power supply voltage at the power
input terminals.
Step 2. Check to see that the power is on. Do not turn the relay off.
Step 3. Measure and record the voltage at all control inputs.
Step 4. Measure and record the state of all output relays.
Table 13.11 Troubleshooting Procedure
All Front-Panel LEDs Dark
➤ Input power not present or fuse is blown.
➤ Self-test failure.
Cannot See Characters on Relay LCD Screen
➤ Relay is de-energized. Check to see if the ALARM contact is closed.
➤ LCD contrast is out of adjustment. Use the steps below to adjust the
contrast.
➤ Remove the relay front panel by removing the six front-panel screws.
➤ Press any front-panel pushbutton. The relay should turn on the LCD
back lighting.
➤ Locate the contrast adjust potentiometer adjacent to the serial port con-
nector.
➤ Use a small screwdriver to adjust the potentiometer.
➤ Replace the relay front panel.
Relay Does Not Respond to Commands From
Device Connected to Serial Port
➤ Ensure that the communications device is connected to the relay.
➤ Verify relay or communications device baud rate setting and other
communications parameters. Check for a cabling error.
➤ Relay serial port may have received an XOFF, halting communications.
Type <Ctrl>Q to send relay an XON and restart communications.
➤ Relay may be set to LMD protocol, which requires an address to turn on the
serial port. Use the front-panel {SET} buttons to view the port setting to see if
the port is set to LMD and to see the address.
Relay Does Not Respond to Faults
➤ Verify that the relay is properly set.
➤ Verify that the test source is properly set.
➤ Verify that the test connections are correct.
➤ Ensure that the analog input cable between transformer secondary and main
board is not loose or defective.
➤ Inspect the relay self-test status with the STA command or with the front-
panel {STATUS} pushbutton.
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