BENSHAW RSi H2 Series - Page 239

PID Control
227
890053-00-02
Code
Description
PID-25
PID P-Gain1
PID-32
PID P-Gain2
Set the output ratio for differences (errors) between the reference (setpoint)
and feedback. As P-Gain is increased, the error is more quickly corrected.
However, if P-Gain is set too high, the mechanical system will begin to
overshoot and at some point may begin to oscillate and become unstable.
EX: If the P Gain 1 is set to 50%, then 50% of the error is output.
PID-26
PID I-Time 1
PID-33
PID I-Time 2
I-Time sets the time to output accumulated errors. When the error is 100%, the
time taken for 100% output is set. When the integral time (PID I-Time) is set to
1 second, 100% output occurs after 1 second of the error remaining at 100%.
Differences in a normal state can be reduced by PID I-Time. When the multi-
function terminal is set to ‘24 (I-Term Clear)’ and is activated, all of the
accumulated errors are deleted.
PID output (final frequency reference) is affected by the gains set at PID-25,
PID-32, and the Acc/Dec times (DRV-03 and DRV-04) to achieve the PID
output change. Therefore, consider the relationship between these values
when configuring the gains and the Acc/Dec times.
PID-27
PID D-Time 1
PID-34
PID D-Time 2
Sets the output amount for the rate of change in errors of the error signal by
the D-Time and uses the result as a corrective signal to the system. Since this
type of control acts to stabilize the transient response of the system, it may be
thought of as electronic damping.
EX: If the differential time (PID D-Time 1) is set to 1 ms and the rate of change
in errors per sec is 100%, output occurs at 1% per 10 ms.
PID-28
PID FF-Gain
Sets the ratio that adds the target to the PID output. Adjusting this value leads
to a faster response.
PID-29
PID Out LPF
Used when the PID controller output changes too quickly or the entire system
is unstable, due to severe oscillation. In general, a lower value (default
value=0) is used to speed up response time, but in some cases a higher value
increases stability. The higher the value, the more stable the PID controller
output is, but the slower the response time.
PID-30
PID Limit Hi
PID-31
PID Limit Lo
Used to set limits of the output of the inverter during PID control. The % is
based on the 60 Hz. setting of the inverter.
PID-35
PID Out Mode
Selects one of the PID output modes to modify the final PID output.
Modifications can be made by adding input values and the main operation
frequency of the PID output to the final PID output value. The following table
lists the 3 modes that are available.
Setting
0
PID Output
1
PID+Main Freq
2
PID or Main
PID-36
PID Out Inv
Set to “No” for normal PI Control. The inverters output will increase when the
feedback signal decreases. (EX: Pressure Control).
Set to “Yes” for inverse PI Control. The inverters output will increase when the
feedback signal increases. (EX: Temperature Control).
PID-37
PID Out Scale
Adjusts the amount of the controller output.
PID-40~46
Step Ref 1~7
Three digital inputs can provide up to 7 different Step References (setpoints)
depending on which inputs are closed (001~111). See settings at IN-65~71 for
PID Step Ref’s L, M and H. With no inputs closed (000), Setpoint is from PID-
10 and PID-11.