Watlow CLS200 - Setup Loop Cascade Menu; Figure 5.4 - Relationship between the Primary Loops Output and the Secondary Loops Setpoint

CLS200 Series User’s Guide
Chapter 5: Enhanced Features
103
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 setpoint
of the secondary loop.
Calculation of new secondary loop setpoint:
Maximum SP
Minimum SP
Base SP
100% Cool 0% Heat
Base SP + |Cool Output Power| * Cool Span +
SP2 = Base SP + |Cool Output Power| * Cool Span + |Heat Output Power| * Heat Span
Primary Loopʼs Output (%)
Secondary Loopʼs Setpoint
100%
|Heat Output Power| * Heat Span
Figure 5.4 — Relationship Between the Primary Loop’s Output and the Secondary Loop’s Setpoint
NOTE! Cascade control cannot be used on the same control loop as ratio control.
However, both features may be used in the same multiloop controller.
Setup Loop Cascade Menu
The setup parameters for cascade control appear under the SETUP LOOP CASCADE menu.
ALARM
SETUP LOOP 02
CASCADE?
Press YES to set up the cascade parameters. The loop currently displayed (loop 02 in this case) will be the
secondary control loop, which performs the actual control.
Primary Loop
Enter the primary loop number. The output percentage of this loop will control the setpoint of the secondary
loop.
ALARM
02 CASCADE
PRIM. LOOP? 03
Selectable values: Any loop except the secondary loop.