Watlow CPC400 User Manual
Page 48
Chapter 2: Installation
CPC400 Series User’s Guide
34
Watlow Anafaze
Doc. 0600-2900-2000
Configuring Outputs
As you choose outputs for control and alarms, bear in mind
the following points:
•
You can enable or disable the control outputs. By de-
fault, heat outputs are enabled and cool outputs are
disabled.
•
You can program each control output individually for
on/off, time proportioning, distributed zero-crossing or
Serial DAC control.
•
You can individually program each control output for
direct or reverse action.
•
Alarm outputs other than the global alarm are non-
latching. See Global Alarm on page 67.
•
Alarms can be suppressed during process start up and
for preprogrammed durations. See Power Up Alarm
Delay on page 100.
•
Alarm outputs can be configured, as a group, to sink to
output during an alarm or stop current flow during an
alarm. See Digital Output Alarm Polarity on page 103.
Control and Alarm Output Connections
Typically control and alarm outputs use external optically-
isolated solid-state relays (SSRs). SSRs accept a 3 to 32V
Î
(
dc) input for control, and some can switch up to 100 Amps
at 480V
Å
(
ac). For larger currents, use silicon control recti-
fier (SCR) power controllers up to 1000 Amps at 120 to
600V
Å
(
ac). You can also use SCRs and a Serial DAC for
phase-angle fired control.
The 34 control and alarm outputs are open collector out-
puts referenced in the CPC400’s common. Each output
sinks up to 60 mAdc to the controller common when on.
NOTE!
Control outputs are sink outputs. They sink cur-
rent when the output is on. Connect them to the
negative side of solid-state relays.
Figure 2.22 shows sample heat, cool and alarm output con-
nections.