WEG CFW700 User Manual - page 41
36 | CFW700
Keypad (HMI) and Basic Programming
E
ng
lis
h
NOTE!
For the level control, the integral gain settings will depend on the time it takes
for the reservoir to go through the minimum acceptable level to the desired
level, with the following conditions:
1. The time for the direct action should be measured with the maximum input
flow and minimum output flow.
2. The time for the reverse action should be measured with minimum input
flow and maximum output flow.
An equation to calculate the initial value of P1021 as a function of the system response time
is presented next:
P1021 = 5.00 / t,
Where: t = time (in seconds)
P1023 – PID Setpoint Filter
Adjustable
Range:
0.00 to 650.00 s
Factory
Setting:
3.0 s
Properties:
-
Access Groups
via HMI:
SPLC
Description:
This parameter sets the value of the constant time of the setpoint filter of the PID regulator
and has the purpose of reducing abrupt changes in the PID setpoint value.
P1024 – PID Regulator Action Type
Adjustable
Range:
0 = Direct
1 = Reverse
Factory
Setting:
0
Properties:
-
Access Groups
via HMI:
SPLC
Description:
The PID action type should be selected as “Direct” when it is necessary that the motor speed is
increased in order to increment the process variable. Otherwise, the “Reverse” should be selected.
Table 4.2: Selecting the PID action type
Motor Speed
Process Variable
Selection
Increases
Increases
Direct
Decreases
Reverse
This characteristic varies with the process type, but direct feedback is most used.
For temperature control or level process, the selection of the action type will depend on the
configuration.
Example: if the inverter runs the motor that removes fluid from the reservoir in a control
level, the action type is reverse as the inverter should increase the motor speed in order to
decrease the level of fluid. In case the inverter is running the motor that is adding fluid in the
reservoir, the action type is Direct.