Watlow CLS User Manual
Page 165
Appendix B: Enhanced Process Control
157
Now press Back several times until the normal loop display appears.
The setpoint of loop 2 will now be equal to one half of the process
variable of loop 2. To complete the ratio setup, configure both loops 1
and 2 for inputs, outputs, and alarms. Please consult the Setup section of
the manual for information on PID loop setup.
Enter the minimum Ratio loop SP. For
this example, we will use 0 gallons per
minute as a minimum
Press Enter.
Enter the maximum Ratio loop SP. For
this example, we will use 7.0 gallons per
minute as a maximum
Press Enter.
Enter the control ratio, which is the mul-
tiple applied to the master Process Vari-
able (the H
2
O flow rate is multiplied by
0.5 to obtain the KOH flow rate set-
point).
Press Enter.
Enter the setpoint differential (or offset).
For this example we have no offset
requirement and will use 0
Press Enter.
Display
User Input
LOOP PROCESS UNITS
ALARM SETPOINT STATUS OUT%
02 RATIO CONTROL
MIN SP? 0.0
LOOP PROCESS UNITS
ALARM SETPOINT STATUS OUT%
02 RATIO CONTROL
MAX SP? 7.0
LOOP PROCESS UNITS
ALARM SETPOINT STATUS OUT%
02 RATIO CONTROL
CTRL: RATIO? 0.5
LOOP PROCESS UNITS
ALARM SETPOINT STATUS OUT%
02 RATIO CONTROL
SP DIFF.? 0