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The RA 19-(X)B and RA 19-1U are configured at the factory for
independent operation of these lines. It is possible to configure these alarm lines to allow multiple 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 internal DIP switches or by external wiring of the I/O connector.
The alarm circuit must not exceed DIP switch specifications: 100mA, 50V d-c, maximum.
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.
N.C. Alarm Line (Open on Failure)The N.C and COM line of each HSF supply provide an open contact (open 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.C. line of one, with the COM line of the next power supply, so the alarm line is connected in series. |
 The equivalent circuit shown here illustrates a close on failure alarm circuit for six power supplies by connecting the internal HSF relays in parallel. |
The equivalent circuit shown below illustrates an open on failure alarm circuit for six power supplies by connecting the internal HSF relays in series.
