MX28B-1200 PRODUCT MANUAL | Revision B |
5.7.1 External Alarm Inputs
Four external alarm inputs with assignable priority levels are available. 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
5.7.2 Alarm 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.
