Watlow CPC400 - Manual (Page 99)

CPC400 Series User’s Guide Chapter 4: Tuning and Control
Doc. 0600-2900-2000 Watlow Anafaze 85
Manually Tuning PID Loops
We recommend using the CPC400's advanced autotuning
and TRU-TUNE+™ adaptive control capabilities to set up
and maintain the PID control parameter settings. See Au-
totuning on page 62. It is, of course, possible to tune the
controller manually. The information in this section is in-
tended as a guide to that end.
When tuning a loop, choose PID parameters that will best
control the process. This section gives PID values for a va-
riety of heating and cooling applications.
NOTE! Tuning is a slow process. After adjusting a loop,
allow about 20 minutes for the change to take ef-
fect.
Proportional Band Settings
Table 4.1 shows proportional band settings for various
temperatures in degrees Fahrenheit or Celsius.
Table 4.1 Proportional Band Settings
As a general rule, set the proportional band to ten percent
of the set point below 1000
° and five percent of the set point
above 1000 ° . This setting is useful as a starting value.
Integral Settings
The controller’s integral parameter is set in seconds per re-
peat. Some other products use an integral term called re-
set, in units of repeats per minute. Table 4.2 shows integral
settings versus reset settings.
Temperature
Set Point
PB
Temperature
Set Point
PB
Temperature
Set Point
PB
-100 to 99 20 1100 to 1199 75 2200 to 2299 135
100 to 199 20 1200 to 1299 80 2300 to 2399 140
200 to 299 30 1300 to 1399 85 2400 to 2499 145
300 to 399 35 1400 to 1499 90 2500 to 2599 150
400 to 499 40 1500 to 1599 95 2600 to 2699 155
500 to 599 45 1600 to 1699 100 2700 to 2799 160
600 to 699 50 1700 to 1799 105 2800 to 2899 165
700 to 799 55 1800 to 1899 110 2900 to 2999 170
800 to 899 60 1900 to 1999 120 3000 to 3099 175
900 to 999 65 2000 to 2099 125 3100 to 3199 180
1000 to 1099 70 2100 to 2199 130 3200 to 3299 185