Position loop - position watch, Example – Rockwell Automation 20D PowerFlex 700S AC Drives with Phase II Control Reference Manual User Manual

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Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011

Chapter 1 Detailed Drive Operation

Position Loop - Position
Watch

The position watch is used to determine when the position feedback reaches a
user defined value. There are two (2) position watches in the PowerFlex 700S.

Parameter 784 [Posit Detct1 In] sets the position feedback that you would like to
watch. By default, [Posit Detct1 In] is linked to parameter 763 [Position Actual].

Note: In order for the value in parameter 763 [Position Actual] to change the
firmware function for the position loop must be turned on by setting parameter
147 [FW Functions En] bit 16 “Position Ctrl” = 1 and the position loop must be
enabled by setting parameter 151 [Logic Command] bit 13 “Position En” = 1.

Parameter 780 [PositDetct1 Stpt] is used to set the position set point for which
to watch.

Setting parameter 740 [Position Control], bit 17 “X Watch1 Dir” = 1 causes the
drive to detect when the position feedback becomes greater than the set point.
Setting [Position Control], bit 17 “X Watch1 Dir” = 0 causes the drive to detect
when the position feedback becomes less than the set point.

Setting parameter 740 [Position Control], bit 16 “X Watch1 En” = 1 enables the
position detection function to detect the next position. Setting [Position
Control] bit 16 “X Watch1 En” = 0 resets position detection.

Setting parameter 741 [Position Status], bit 8 “Posit Watch1” = 1 indicates that
the position set point has been passed.

Example:

• Set parameter 147 [FW Functions En], bit 22 “PosWtch/Dtct” = 1.

• Link parameter 784 [Posit Detct1 In] to parameter 240 [Encdr1 Position].

• Set parameter 780 [PositDetct1 Stpt] = 100,000 counts.

• Set parameter 740 [Position Control], bit 17 “X Watch1 Dir” = 1.

• Set parameter 740 [Position Control], bit 16 “X Watch1 En” = 1.

Position Watch 1

763

780

741

08

Position Actual

Position Control

(X Watch 1 En)
(X Watch 1 Dir)

PositDetct1 Stpt

Position Status
(Posit Watch1)

784

Posit Detct1 In

Link

740

16

740

17

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