Watlow 8PID Controller - Manual (Page 27)

22
1. As a TTL signal by connecting to "AL" pin and "GND".
ON < 0.5V at 4ma sink
OFF = 5V at 400ohm source resistance
2. To drive A 3-32V type solid state relay. TRUE LOGIC
Connect "AL" pin to - side of control input.
Connect +5V (pin "SP7" for S.N.P2000 and above) to + side of control
input.
When output is on, relay turns on.
When output is off, relay turns off.
3. To drive a 3-32V type solid sate relay. INVERTED LOGIC
Connect "AL" pin to + side of relay.
Connect "GND" pin to - side of relay.
When output is on, relay turns off.
When output is off, relay turns on.
5.7 ALARM EXPANDER AND DIGITAL I/O
The optional alarm expander provides EEROM [memory] storage of control parameters
and is highly recommended in critical situations. The Alarm expander also provides for
22 digital input and output lines. Please see the separate manual for this device.