8.18
SEL-551 Relay Instruction Manual Date Code 20110408
Testing and Troubleshooting
Relay Calibration
Relay Calibration
The SEL-551 is factory-calibrated. If you suspect that the relay is out of
calibration, please contact the factory.
Factory Assistance
We appreciate your interest in SEL products and services. If you have any
questions or comments, please contact us at:
Schweitzer Engineering Laboratories, Inc.
2350 NE Hopkins Court
Pullman, WA 99163-5603 USA
Phone: +1.509.332.1890
Fax: +1.509.332.7990
Internet: www.selinc.com
E-mail: info@selinc.com
LCD contrast is out of adjustment. Use the steps below to adjust the contrast.
1. Remove the relay front panel by removing
the three front-panel screws.
2. Press any front-panel button. The relay
should turn on the LCD back lighting.
3. Locate the contrast adjust potentiometer
directly adjacent to the EN LED.
4. Use a small screwdriver to adjust the poten-
tiometer.
5. Replace the relay front panel.
Relay Does Not Respond to Commands From Device Connected to Serial Port
Communications device
is not connected to the relay.
Connect a communications device.
Relay or communications device
at incorrect baud rate or other communication
parameter incompatibility, including cabling
error.
Relay serial port has received an
XOFF, halting communications.
Type <Ctrl+Q> to send relay an XON and
restart communications.
Relay Does Not Respond to Faults
Relay is set improperly. Review the relay settings. See Section 4: Setting
the Relay.
Improper test settings. Restore operating settings.
CT connection wiring error. Confirm CT wiring.
The analog input cable between the
transformer secondary and the main
board is loose or defective.
Reseat both ends of the analog input cable,
observing proper ESD precautions.
Failed relay self-test.
Table 8.4 Troubleshooting Procedures (Sheet 2 of 2)
Symptom/Possible Cause Diagnosis/Solution
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