Watlow Series D8 - Manual (Page 56)

Chapter 2: Installation Series D8 User’s Guide
38 Watlow Anafaze Doc. 0600-3120-2000
Analog Outputs
Analog outputs can be provided by using a Dual DAC or Se-
rial DAC module to convert the open collector outputs from
the controller. Use multicolored stranded shielded cable for
analog outputs. Analog outputs generally use a twisted pair
wiring. The following sections describe how to connect the
Dual DAC and Serial DAC modules to power the controller
outputs and the load.
Wiring the Dual DAC
A Dual DAC module includes two identical circuits. Each can
convert a distributed zero cross (DZC) signal from the con-
troller to a voltage or current signal. Watlow Anafaze strong-
ly
recommends using a power supply separate from the
controller supply to power the Dual DAC. Using a separate
power supply isolates the controller’s digital logic circuits and
analog measurement circuits from the frequently noisy devic-
es that take the analog signal from the Dual DAC.
Several Dual DAC modules may be powered by one power
supply. Consult the Specifications chapter for the Dual
DAC’s power requirements. Also note in the specifications
that the Dual DAC does not carry the same industry approvals
as the Serial DAC.
Figure 2.23 Dual DAC with Current Output
TB50 or TB18
+5V 1
Control Output
+5V CTRL Supply 1
2
3
4
5
6
DZC CTRL PID Output
+12/24 Vdc External
Power Supply
+Vdc Load Connection
-mAdc Load Connection
-External Power
Supply/ Vdc Load
Connection
Dual DAC
mA Load
12 to 24 Vdc Power Supply
+ -
+
-