WEG CFW-11 Series, Programming Manual

Page: 275 / 307

20-3
20
PID Regulator [46]
20.2 COMMISSIONING
Before doing a detailed description of the parameters related to this function, a step by step guide for putting
the PID into operation will be presented.
NOTE!
In order that the PID function works properly, it is fundamental to verify if the inverter is configured
correctly to drive the motor at the desired speed. Therefore, verify the following settings:
Torque boost (P0136 and P0137) and slip compensation (P0138), if it were in the V/f control mode.
Having run the self-tuning if it were in the vector mode.
Acceleration and deceleration ramps (P0100 to P0103) and current limit (P0135 for V/f and
VVW control, or P0169/P0170 for vector control).
Configuring the PID Function
1) To select the especial function: PID Regulator (P0203 = 1)
When the PID function is enabled, by setting P0203 = 1 via HMI, the following parameters are changed automatically:
P0205 = 10 (Reading Parameter Selection 1: Setpoint PID #).
P0206 = 9 (Reading Parameter Selection 2: Process Var. #).
P0207 = 2 (Reading Parameter Selection 3: Motor Speed #).
P0223 = 0 (FORWARD/REVERSE Selection - LOCAL Situation: Always FORWARD).
P0225 = 0 (JOG Selection – LOCAL Situation: Disabled).
P0226 = 0 (FORWARD/REVERSE Selection - REMOTE Situation: Always FORWARD).
P0228 = 0 (JOG Selection - REMOTE Situation: Disabled).
P0236 = 3 (AI2 Signal Function: Process Variable).
P0265 = 22 (DI3 Function: Manual/Automatic).
The DI3 function, defined by the parameter P0265, works in the following manner:
Table 20.1 - DI3 operation mode for P0265 = 22
DI3 Operation
0 (0 V) Manual
1 (24 V) Automatic
2) To define the type of PID action that the process requires: direct or reverse. The control action must be direct
(P0527 = 0) when it is necessary that the speed increases for the process variable to increase. Otherwise,
select reverse (P0527 = 1). See
Figure 20.2 on page 20-4 .
Examples:
a)
Direct: A pump driven by an inverter filling up a reservoir, with the PID controlling its level. In order that the
level (process variable) increases, it is necessary that the flow increases, which is obtained with the increase
of the motor speed.
b) Reverse: A fan driven by an inverter doing the refrigeration of a cooling tower, with the PID controlling its
temperature. In order that the temperature (process variable) increases, it is necessary that the ventilation be
reduced, by means of the reduction of the motor speed.