946 Controller Instruction Manual
pg. 77
8 Connecting Relay and Analog Outputs
Relay and analog outputs require 2.5 sec time delay to stabilize after power application.
8.1
Connecting 946 Relay Outputs
There are twelve relays available in the 946 Controller which can be used to control the operation of
devices associated with a vacuum system. Relay contacts can be accessed through the 25 pin “Relay
Output” D-sub connector on the back of the AIO module.
Relays used in the 946 are normally open (NO) SPDT relays. During the 946 power-up process, a 2.5
sec. delay is implemented to ensure that all relays remain in the normally open state until reliable control
signals are available.
If normally closed relay outputs are required, an external conversion is required.
The relays are controlled with signals from the main microprocessor in the 946. The time required to
process a pressure signal results in a relay activation time delay of between 50 to 100 msec
.
8.1.1 Pin Out for the 946 Relay Output
Table 8-1 identifies the pins for the 25-pin "D" connector on the AIO/Power module that provides the
connection to the relay outputs. 12 relays are built into the controller and 4 relays are assigned to each
sensor module slot. If a single sensor module such as a CC or a HC is present, all four of these relays are
assigned to the one sensor. If a dual sensor module such as a Pirani, CP, or Capacitance Manometer is
used, 2 relays are assigned to each sensor.
Pin Description
Pin
Description
1 Relay 1 NO
14 Relay 7 NO
2 Relay 1 Common
15 Relay 7 Common
3 Relay 2 NO
16 Relay 8 NO
4 Relay 2 Common
17 Relay 8 Common
5 Relay 3 NO
18 Relay 9 NO
6 Relay 3 Common
19 Relay 9 Common
7 Relay 4 NO
20 Relay 10 NO
8 Relay 4 Common
21 Relay 10 Common
9 Relay 5 NO
22 Relay 11 NO
10 Relay 5 Common
23 Relay 11 Common
11 Relay 6 NO
24 Relay 12 NO
12 Relay 6 Common
25 Relay 12 Common
13 No Connection
Table 8-1 Pin Out for the 946 Relay Output