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6.0 UPS Monitoring
6.4 Computer interface port
The computer interface port is diagramed below for your reference. Those with technical
abilities wishing to use this port in a special application should be aware of the following
limitations and capabilities of the interface.
■ Outputs at pins 3, 5 and 6 are actually open collector outputs which must be pulled up
to a common referenced supply no greater than +40 Vdc. The transistors are capable of
a maximum non-inductive load of 25 mAdc. Use only Pin 4 as the common.
■ The output at Pin 2 will generate a LO to HI RS-232 level upon transfer of the output
load to power derived from the UPS’s battery. The pin is normally at a LO RS-232 level.
■ The UPS will shut down when a HI RS-232 level, sustained for 4.5 s, is applied to Pin
1. The UPS responds to this signal, following a delay, only during mains failures (load is
operating from the UPS’s internal power source).
■ An unregulated +24 Vdc appears at Pin 8 of the interface port whenever the UPS is
powered. The supply is limited to 40 mAdc maximum.