ST950S Plus+ Installation and Commissioning Manual
Table 27. CIC/CTB Digital Input Functions (continued)
Pin
Legend
Function
2
GND
For connection to the other switch contact.
This two-way connector provides for an optional digital input. This may be used for connection to
switches such as a door alarm switch.
3.15.9. CIC/CTB Interfaces: ZXO Input
The ZXO or Zero Crossing input is connected to the secondary of a toroidal transformer. The CIC
processes the AC waveform from this transformer to produce timing signals where the AC waveform
crosses 0V. These timing signals are used by the system for confirmation of the system clocks.
Table 28. CIC/CTB ZXO Pin Out
Pin
Legend
Function
1
AC IN1
ZXO AC In (Red)
2
GND
ZXO AC In (Yellow)
3
NC
No Connection
3.15.10. CIC/CTB Interfaces: Logic Supply Distribution (+24V DC)
The 24V logical supply is sourced from a DIN rail mounted PSU located on the left panel of the cabinet.
This connects to the first CIC/CTB at PL18 ‘24V DC PSU’. The connector details are as follows:
Table 29. CIC/CTB Logic Supply Pin Out
Pin
Legend
Function
1
+24V OUT
Not currently used.
2
+24V IN
+24V DC in from the DIN rail mounted PSU
3
GND
0V Return for the +24V DC PSU
4
GND
0V Return for the +24V DC PSU
The CIC/CTB provides 24V DC power to the ST950 CPU card via PL5 (‘RLYA & RLYB Molex
connector) and the GSPI IN connectors.
3.15.11. CIC/CTB Interfaces: Relay A and Relay B and Consolidated Relay
Relay A and Relay B are signals from the ST950 CPU that in normal operation are asserted (pulled
low). If the ST950 detects a major fault it may de-assert either Relay A or Relay B or both Relays.
CIC/CTB#1 connects to the ST950 Relay A and Relay B via a 6- way Molex connector PL5. Detail for
this connection is as follows:
Page 70