American Power Conversion MX28B1200, MX28B2400+27V manual External Alarm Inputs, Alarm Outputs

Rev 1 MX28B-1200+27V PRODUCT MANUAL

5.7.1External Alarm Inputs

Four external alarm inputs with assignable priority levels are availa ble. These alarm inputs respond to external dry contact closures between normally open (NO) and common (C) or contact openings between normally closed (NC) and C (see Table 5-1).

External Alarm Source	Connect To Input
(non-alarm state)	Alarm Terminals
OPEN	NO-C
CLOSED	NC-C

Table 5-1. External Alarm Input Definition

Table 5-2 shows the external alarm input connection designations. Connector J4 is located on the alarm interface board mounted in the space above the control unit. Systems are shipped with jumper wires connecting each NC and corresponding C contact. A jumper wire should be removed only if the corresponding NC-C contacts are going to be used.

EXTERNAL	J4 TERMINAL
ALARM	DESIGNATION	USER ALARM NOTES
INPUT	(NO-NC-C)
#1	NO1-NC1-C1	___________________________
#2	NO2-NC2-C2	___________________________
#3	NO3-NC3-C3	___________________________
#4	NO4-NC4-C4	___________________________

Table 5-2. External Alarm Input Connections

5.7.2Alarm Outputs

There are eight alarms available that provide outputs via Form “C” relay contacts. The last two of these are pre-assigned as the Minor and Major alarm outputs. The Major relay is energized (NO-C contacts closed) during normal (non-alarm) operating conditions ; all the other relays energize when an alarm condition occurs. The other six outputs are initially designated as “Relay 1” through “Relay 6” (the user may assign more meaningful names if desired). The various system alarm conditions can be assigned to any of the eight alarm outputs.

Table 5-3 shows the alarm output connection designations. Connectors J1 and J2 are located on the alarm interface board mounted in the space above the control unit. The relay contacts should only be used to switch resistive loads of 0.5 amperes or less at 60 volts or less.

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