KEPCO RA 19-4B - Manual (Page 26)

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RA 19-4B 011409
2.4.4 ALARM CONFIGURATIONS
The HSF Power Supplies each provide a normally closed (N.C.) and normally open (N.O.) line
referenced to common (COM) for use as an alarm at the users discretion. The N.C. line opens
upon failure, the N.O. line closes upon failure. The RA 19-4B is configured at the factory for
independent operation of these lines. It is possible to configure these alarm lines to allow multi-
ple power supplies to provide a failure indication using the N.O. (close on failure) lines, N.C
(open on failure) lines, or both. Each alarm circuit can be configured in two ways: either by inter-
nal DIP switches or by external wiring of the I/O mating connector. Use external wiring of the I/O
mating connector if DIP switch specifications noted in the following CAUTION will be exceeded.
CAUTION: The user is responsible for ensuring that the alarm circuit does not exceed
the HSF alarm relay switching specifications: 1A @ 30V d-c or 0.5A @ 125V
a-c. If the alarm circuit is configured using the rear panel DIP switches, the
user is responsible for ensuring that the alarm circuit does not exceed DIP
switch specifications: 100mA, 50V d-c, maximum.
2.4.4.1 N.O. ALARM LINE (CLOSE ON FAILURE)
The N.O. and COM line of each HSF supply provide a closed contact (short circuit) upon failure.
To configure multiple power supplies so that a failure of any supply produces a failure indication,
it is necessary to connect the N.O. lines in parallel and the COM lines in parallel.
2.4.4.1.1 CLOSE ON FAILURE USING INTERNAL DIP SWITCHES
Close on failure for multiple power supplies can be accomplished by setting DIP switch positions
6 and 7 to ON (closed). associated with each adjacent slot included in the alarm circuit. For
example, for PS1 and PS2, set DIP switch 2, positions 6 and 7 to ON (closed). The failure indi-
cation (short circuit) will be present across both N.O.1 and COM1, and N.O.2 and COM2. Figure
2-11 is a simplified diagram illustrating a close on failure alarm configuration for four power sup-
plies using internal DIP switches.