34 HPFF12 NAC Expander — P/N 53576:B3 10/1/2018
Trouble Supervision Trouble Reporting
If the current in any NAC exceeds 3.5 A due to excessive loading, the unit disables its output for approximately 8 seconds. The unit will
then attempt to re-engage the NAC output(s), and will disable it if the 3.5 A is exceeded again. If an overload condition exceeding 4.0 A
exists for more than two re-engagements, the unit will illuminate the corresponding yellow SIG TRBL LED(s) steady and generate a
general trouble. This is a latched overload condition, but the unit will keep attempting to re-engage the NAC output. The general trouble
transfers only the Trouble contact until the alarm condition clears.
4.2.7 Ground Fault Detection
A ground fault trouble will be generated if there is 50 K ohms or lower between Earth Ground and the field wiring, except the initiating
device SIGNAL 1 and SIGNAL2 inputs and TB2 AC FAIL and TROUBLE contacts. The signal inputs are optically-isolated from the
HPFF’s circuitry and will be supervised by the FACP. TB2’s contacts are dry contacts and will be supervised by the FACP.
4.2.8 NAC Overload Protection and Indication
If the current in any NAC exceeds the 3.5 A maximum, the unit disables its output for approximately 8 seconds. The unit will then
attempt to re-engage the NAC output(s), and will disable it if the 3.5 A is exceeded again. If an overload condition exceeding 4.0 A
exists for more than two re-engagements, the unit will illuminate the corresponding yellow SIG TRBL LED(s) steady and transfer the
TB2’s TROUBLE contacts. This is a latched overload condition, but the unit will keep attempting to re-engage the NAC output while in
alarm.
To clear the permanently latched overload condition, the AC must be cycled and the battery momentarily disconnected, or just press
SW2 (microprocessor reset) on the Control circuit board.
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