Allen-Bradley PowerFlex 70 Reference Manual page 144

Process PI Loop
144
Configuration Example:
The PI reference meter and PI feedback meter should be displayed as positive and
negative values. Feedback from our dancer comes into Analog Input 2 as a 0-10V
DC signal.
• [PI Reference Sel] = 0 "PI Setpoint"
• [PI Setpoint] = 0 %
• [PI Feedback Sel] = 2 "Analog In 2"
• [PI Reference Hi] = 100 %
• [PI Reference Lo] = –100 %
• [PI Feedback Hi] = 100 %
• [PI Feedback Lo] = –100 %
• [Analog In 2 Hi] = 10V
• [Analog In 2 Lo] = 0V
PI Feedback Scaling
[Torque Ref A Sel] = "Analog In 1"
[Analog In 2 Hi] [PI Feedback Hi]
10 V 100 %
[Analog In 1 Lo] [PI Feedback Lo]
0V -100 %
Now 5V corresponds to 0% on the PI Feedback, so we will try to maintain a PI
setpoint of 0% (5V). Now [PI Ref Meter] and [PI Fdback Meter] are displayed as
bipolar values.
PI Setpoint
This parameter can be used as an internal value for the setpoint or reference for
the process. If [PI Reference Sel] points to this Parameter, the value entered here
will become the equilibrium point for the process.
PI Output
The PI Error is then sent to the Proportional and Integral functions, which are
summed together.
PI Gains
The PI Proportional Gain and the PI Integral Gain parameters determine the
response of the PI.
The PI Proportional Gain is unitless and defaults to 1.00 for unit gain. With PI
Proportional Gain set to 1.00 and PI Error at 1.00% the PI output will be 1.00%
of maximum frequency.
Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013