GE AF-650 GP Design And Installation Manual page 71

Application Set-Up Examples
Parameter
Parameter PI-36 Process PID Diff. Gain Limit
Parameter PI-38 Process PID Feed Forward
Factor
Parameter E-64 Pulse Filter Time Constant #29
(Pulse term. 29), parameter E-69 Pulse Filter
Time Constant #33 (Pulse term. 33),
parameter AN-16 Terminal 53 Filter Time
Constant (Analog term 53),
parameter AN-26 Terminal 54 Filter Time
Constant (Analog term. 54)
6 6
Table 6.20 Relevant Parameters for Process Control
Function
Restore the frequency converter
1) Set motor parameters:
Set the motor parameters according to nameplate
data
Perform a full auto tune
2) Check that motor is running in the right direction.
When motor is connected to frequency converter with straight forward phase order as U–U; V–V; W–W motor shaft usually turns clockwise
seen into shaft end.
Press [Hand]. Check shaft direction by applying a
manual reference.
If motor turns opposite of required direction:
1. Change motor direction in
parameter H-08 Reverse Lock
2. Turn off mains - wait for DC-link to discharge -
switch 2 of the motor phases
Set configuration mode
Set local mode configuration
3) Set reference configuration, i.e. the range for reference handling. Set scaling of analog input in parameter group AN-##
Set reference/feedback units
Set min. reference (10 °C)
Set max. reference (80 °C)
If set value is determined from a preset value
(array parameter), set other reference sources to
No Function
4) Adjust limits for the frequency converter:
Set ramp times to an appropriate value as 20 s
68
Description of function
If there are quick changes in reference or feedback in a given application - which means
that the error changes swiftly - the differentiator may soon become too dominant. This is
because it reacts to changes in the error. The quicker the error changes, the stronger the
differentiator gain is. The differentiator gain can thus be limited to allow setting of the
reasonable differentiation time for slow changes.
In application where there is a good (and approximately linear) correlation between the
process reference and the motor speed necessary for obtaining that reference, the Feed
Forward Factor can be used to achieve better dynamic performance of the Process PID
Control.
If there are oscillations of the current/voltage feedback signal, these can be dampened by
a low-pass filter. This time constant represents the speed limit of the ripples occurring on
the feedback signal.
Example: If the low-pass filter has been set to 0.1s, the limit speed is 10 RAD/s (the
reciprocal of 0.1 s), corresponding to (10/(2 x π)) = 1.6 Hz. This means that all currents/
voltages that vary by more than 1.6 oscillations per second is damped by the filter. The
control is only carried out on a feedback signal that varies by a frequency (speed) of less
than 1.6 Hz.
The low-pass filter improves steady state performance, but selecting a too large filter time
deteriorates the dynamic performance of the Process PID Control.
Parameter Setting
H-03 [2] Restore - make a power cycling - press reset
P-02 to P-07 As stated on motor nameplate
F-04 & F-05
P-04 [1] Enable complete auto tune
H-08 Select correct motor shaft direction
H-40 [3] Process
H-45 [0] Speed Open Loop
[60] °C Unit shown on display
F-51
10 °C
F-52
80 °C
F-53
C-05
[0] 35%
Par . C − 05
Ref =
100
= 24, 5° C
Parameter F-64 Preset Relative Reference to parameter F-68 Relative
Scaling Reference Resource [0] = No Function
F-07 20 s
F-08 20 s
DET-767c All rights reserved.
0
× Par . F − 53 − par . F − 52
MG35M402