Rockwell Automation 20B PowerFlex 700 AC Drives Vector Control (v4.001 and up) - Manual (Page 129)

Rockwell Automation Publication 20B-UM002G-EN-P - July 2014 129
Application Notes Appendix C
• Homing to Limit Switch with Encoder Feedback
When “Find Home” is commanded, the homing routine is run when a
start command is issued. The Homing bit (11) in [Profile Status] will be
set while the homing routine is running. The drive will ramp to the speed
and direction set in [Find Home Speed] at the rate set in [Find Home
Ramp] until the digital input defined as Home Limit is activated. The
drive will then reverse direction at 1/10 the [Find Home Speed] to the
point where the Home Limit switch activated and stop.
Figure 11 shows the sequence of operation for homing to a limit switch
with encoder feedback (without a marker pulse). [Encoder Z Chan] must
be set to “Pulse Input” or “Pulse Check.”
Figure 11 - Homing to a Limit Switch
• Homing to Limit Switch w/o Encoder Feedback
When “Find Home” is commanded, the homing routine is run when a
Start command is issued. The Homing bit (11) in [Profile Status] will be
set while the homing routine is running. The drive will ramp to the speed
and direction set in [Find Home Speed] at the rate set in [Find Home
Ramp] until the digital input defined as Home Limit is activated. The
drive will then decelerate to zero. If the switch is no longer activated, the
drive will reverse direction at 1/10 the [Find Home Speed] to the switch
position and then stop. The Home Limit switch will be active when
stopped.
Figure 12 shows the sequence of operation for homing to a limit switch
without encoder feedback.
Figure 12 - Homing to Limit Switch (No Feedback)
20 25 30 35 40 45 50 55
0
5
10
15
20
25
30
Find Home Command
Start Command
Home Limit Input
At Home
Homing
-50
0
50
100
150
200
250
60 15 65
[Encoder Speed], 415 [Units Traveled], 701 [Dig In Status], 216 [Profile Status], 700
Encoder Speed
Profile Status
Units Traveled
Digital In Status
Find Home Command Start Command
Home Limit Input
At Home Homing
-50
0
50
100
150
200
20 25 30 45 0 35
[Speed Feedback], 25 [Dig In Status], 216 [Profile Status], 700