Figure 7.16 Aft Command Response; Table - Schweitzer Engineering Laboratories SEL-751 Instruction Manual

7.22 Communications
Communications Protocols
SEL-751 Relay
AFT Command (Arc-Flash Detection Channels Self-Test)
Use the AFT command (Access Level 2) to initiate a self-test of the arc-flash
detection channels 1 to 8. This test requires that the relay has the SEL
2 AVI/4 AFDI card or 8 AFDI card in Slot E and the external fiber-optic
connections are complete. The test checks the integrity of the arc-flash
detection system. Figure 7.16 shows an example of the AFT command
response with a 2 AVI/4 AFDI card in Slot E. Refer to Section 11: Testing and
Troubleshooting for details on the arc-flash self-tests.
=>>AFT <Enter>
Arc Flash Diagnostic in progress . . . . . . . . . . . . .
SEL-751
FEEDER RELAY
Channel # Sensor Test Light Limits
Type
AF Input 1 Fiber
AF Input 2 Fiber
AF Input 3 None
AF Input 4 Point
=>>

Figure 7.16 AFT Command Response

The relay asserts the AFALARM Relay Word bit when the sensor diagnostics
fail or the relay detects excessive ambient light. Sensor diagnostics failure is
indicated by the assertion of the AFSnDIAG Relay Word bits and excessive
ambient light is indicated by the assertion of the AFSnEL Relay Word bits,
where n = 1 to 8. The relay asserts the AFSnEL Relay Word bits when the
corresponding TOLn Relay Word bits stay asserted continuously for
10 seconds.
ANALOG Command
Use the ANA command to test an analog output by temporarily assigning a
value to an analog output channel (see Table 7.9 for the command description
and format). After entering the ANA command, the device suspends normal
operation of the analog output channel and scales the output to a percentage of
full scale. After assigning the specified value for the specified time, the device
returns to normal operation. Entering any character (including pressing the
space key) ends the command before it reaches the specified interval
completion.
You can test the analog output in one of the following two modes:
➤
Fixed percentage: Outputs a fixed percentage of the signal for
a specified duration
➤
Ramp: Ramps the output from minimum to maximum of full
scale during the time specified
Instruction Manual
Date: 12/09/2010
Time Source: Internal
Measured
Min(%) Max(%) Test Light(%) Diagnostic
10.00 100.00 31.94
10.00 100.00 27.08
---.-- ---.-- ---.--
0.10 79.00 2.27
ECT
Time: 09:20:13
Sensor Excess Ambient
Light
Pass OK
Pass OK
--- ---
Pass OK
Date Code 20170927