Rockwell Automation WebPak 3000 DC Drive Application Workbook Version 1.1 - Manual (Page 65)

Configuring the Position Outer Loop 11-3
▲
Set POS PI PROP GAIN (P.236) using the same test formula as for KP as shown
at the end of this section. P.236 becomes the value for P.248.
▲
Set POS PI LEAD FREQ (P.234) to 0.2 radians/seconds. P.234 becomes the
value for P.249.
▲
Set POS LEADLAG LOW FREQ (P.231) to the same value as SPEED CROSS OVER
(P.133). P.231 becomes the value for P.246.
▲
Set POS LEADLAG RATIO (P.232) to 7.5. P.232 becomes the value for P.247.
▲
If required, tune the position loop performance by increasing POS PI PROP GAIN
(P.236). However, since raising the value of P.236 also increases POSITION
CROSS OVER (P.239), the value of POS PI LEAD FREQ (P.234) may also need to
be increased.
▲
Set POS LEADLAG BYPASS (P.255). The use of the lead/lag function for the
position feedback is recommended for applications with or without position
gain profiling. Bypass of this function can be accomplished using
POS LEADLAG
BYPASS (P.255).
Range: 0.10 to 128.00 P.236 =
Range: 0.00 to 141.37 RAD / S P.234 = 5$'6
Range: 1.00 to 34.90 RAD / S P.231 = RAD / S
Range: 2 to 20 P.232 =
Range: 0.10 to 128.00 P.236 =
Range: ON , OFF P.255 =
Testing the Value of Position Cross Over (P.239)
Use the following formula if the value of P.239 exceeds 5 radians/second.
KP = (PCO x S) / (LS x (PV% / 100))
Where:
•
PCO = POSITION CROSS OVER (P.239)
•
KP = POS PI PROP GAIN (P.236)
•
PV % = POS VERNIER PERCENT (P.238)
•
S = STORAGE (P.857)
•
LS = TOP LINE SPEED (P.020)
Example:
If POSITION CROSS OVER (P.239) is nominally set to 5.0 radians/seconds:
•
PV % (P.238) is set to 10
•
S = 5 feet
•
LS = 20 feet/second
Then: KP = (5 x 5) / (20 x (10 / 100)) = 12.5
In this example, since KP did not exceed 60, PCO could be increased to raise the
value of KP to maximize position loop performance.