13-46
Testing and Troubleshooting
Date Code 20011205
SEL-311B Instruction Manual
R
ELAY
T
ROUBLESHOOTING
Inspection Procedure
Complete the following procedure before disturbing the relay. After you finish the inspection,
proceed to the
Troubleshooting Procedure
.
1. Measure and record the power supply voltage at the power input terminals.
2. Check to see that the power is on. Do not turn the relay off.
3. Measure and record the voltage at all control inputs.
4. Measure and record the state of all output relays.
Troubleshooting Procedure
All Front-Panel LEDs Dark
1. Input power not present or fuse is blown.
2. Self-test
failure.
Cannot See Characters on Relay LCD Screen
1. Relay is deenergized. Check to see if the ALARM contact is closed.
2. LCD contrast is out of adjustment. Use the steps below to adjust the contrast.
a) Remove the relay front panel by removing the six front-panel screws.
b) Press any front-panel button. The relay should turn on the LCD back lighting.
c) Locate the contrast adjust potentiometer adjacent to the serial port connector.
d) Use a small screwdriver to adjust the potentiometer.
e) Replace the relay front panel.
Relay Does Not Respond to Commands From Device Connected to Serial Port
1. Ensure that the communications device is connected to the relay.
2. Verify relay or communications device baud rate setting and other communications
parameters. Check for a cabling error.
3. Relay serial port may have received an XOFF, halting communications. Type
<CTRL>Q
to
send relay an XON and restart communications.
4. Relay may be set to LMD protocol, which requires an address to turn on the serial port.
View the port setting using the front-panel SET buttons to see if the port is set to LMD and
to see the address.
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