Data Translation DT9871, User Manual

Page: 62 / 134

Chapter 4
62
Connecting Digital Output Signals
The digital output lines of a TEMPpoint, VOLTpoint, or MEASURpoint instrument act as
solid-state relays. The customer-supplied signal can be ±30 V at up to 400 mA (peak) AC or
DC.
You can use the digital output lines of the instrument to control solid-state or mechanical
relays or high-current electric motors.
Figure 27 shows how to connect digital output signals
to line 0 of the instrument to control a motor relay.
Figure 27: Switching up to 30 V at 400 mA
Digital Out 0
Digital Out 0 pin 10
120 V AC
or 240 V AC
Relay
Motor
10 A
Fuse
Neutral Hot
30V DC @ 400 mA
+ *
–
pin 29
Instrument
Digital I/O Connector
*Output can switch AC or DC.
Controlled by
Software
Note: Relay, motor, and circuits must be properly rated. Reinforced isolation must be
maintained between the digital output circuits and the relay/motor switching circuits.