Watlow CLS200 - Manual (Page 134)

Chapter 6: Enhanced Features CLS200 Series User’s Guide
118 Watlow Anafaze Doc.# 0600-3050-2000
Notes about this application:
• This is not a thermocouple curve type of signal and re-
quires a linear input range in the recorder.
• To complete this configuration, the loop 2 output must
be enabled and tailored to meet the requirements of
the data-application. In this example, the data logger
requires an analog input of 4 to 20 mA.
• The CLS200 Series controllers must be used with a
Watlow Anafaze Serial DAC.
Consult Chapter 4, Setup for information on setting up the
other options of the controller.
Cascade Control
Cascade control is used to control thermal systems with
long lag times, which cannot be as accurately controlled
with a single control loop. The output of the first (primary)
loop is used to adjust the setpoint of the second (secondary)
loop. The secondary loop normally executes the actual con-
trol.
The cascade control feature allows the output percentage of
one control loop to determine the setpoint of a second con-
trol loop. By adjusting the setpoint (SP) parameters, the
user can adjust the influence that the primary loop has on
the setpoint of the secondary loop. See Figure 6.4.
Some applications, such as aluminum casting, use two-
zone cascade control where the primary output is used for
the primary heat control and the cascaded output is used
for boost heat. The CLS200 allows you to use the primary
heat output for both control and for determining the set-
point of the secondary loop.