Rockwell Automation 20B PowerFlex 700 AC Drives Vector Control (v4.001 and up) - Manual (Page 119)

Rockwell Automation Publication 20B-UM002G-EN-P - July 2014 119
Application Notes Appendix C
End Travel Limit for Digital Inputs
End Travel Limit is enabled by selecting “End Limit” as one of the digital inputs
in [Digital In1-6 Select]. A “low” at this input (opposite logic) will cause the
drive to do a fast decel (0.1 sec) and turn off. This Stop limit will be enforced only
in the direction the drive was running when the switch was activated
(momentarily or continuously, see “C” in
Figure 8 ).
A Start command in the same direction will only allow 0 Hz to be commanded. A
Start in the opposite direction will allow motion with a speed command from the
selected speed reference. If TorqProve is Enabled, the drive will hold zero speed
for a time determined by [ZeroSpdFloat Time], parameter 605.
Two different input switches can be connected in series to one digital input to
provide an end limit at both ends of the application (for example, lift, conveyor,
etc.). With proper set up, the drive will automatically apply the proper stopping
based on the direction of the load even though only one digital input is being
used.
Limit Switch Set up
1. Move the load to a position between the two decel switches (“A” in
Figure 8 ).
2. Select the switches in [Digital In1-6 Select]. If switches are only used on
one end of travel, simply keep the load off of both switches when selecting
in [Digital In1-6 Select].
If the set up is done incorrectly, the application will not move or will move at an
incorrect (slower) speed. This can be corrected by selecting “Not Used” for both
limit switches in [Digital In1-6 Select]. Then, move the load between the Decel
Switches and select the limit switches again in [Digital In1-6 Select].
Figure 8 - Limit Switch Operation
Minimum Speed Refer to Reverse Speed Limit on page 136 .
IMPORTANT When properly set up, the drive will remember its location during power cycles
(or power loss) unless the load is manually moved during power down
conditions. If this occurs, simply reset the feature using the procedure above.
End Limit
Switch
Decel Limit
Switch
Decel Limit
Switch
End Limit
Switch
C B A C B
Preset 1 Speed (Slow) Commanded Speed (Normal Operating Speed)
Stop
Preset 1 Speed (Slow) Commanded Speed (Normal Operating Speed)
this direction
only
Stop
this direction
only