Delta RMC151 - Manual (Page 1015)

9 Register Reference
Note:
If the Direct Output Status bit is on, the Overtravel bits will not be set.
Moving Toward the Valid Travel Range
While the axis is outside the valid travel range, as defined by the Travel Limits, any
motion commands the move the axis toward the valid travel range will be accepted, even
if they don't move the axis entirely into the valid range.
Notice that if the axis is outside the valid travel range, in open loop, and is drifting
slightly away from the valid range, issuing a closed loop motion command may again
trigger an overtravel error. This is because the target position starts at the actual
position, velocity and acceleration at the time the command is issued. This means the
target will continue moving away from the valid range while accelerating to turn around.
This will trigger an overtravel error. To avoid this, first issue a Hold Current Position (5)
command, then the motion command. Or, simply use an open loop move to move into
the valid range.
Truncating a Motion Command
Any motion command issued with a Requested Position that is outside of the travel limits
will be set to the closest travel limit, and the Command Modified error bit will be set. The
error bit will cause a Halt to occur if the Auto Stops are configured to do so and the Direct
Output Status bit is off. If the axis is outside of the travel limits when a move command is
issued, the axis will only be allowed to move in the direction that brings it closer to the
limit.
9.2.2.7.2. Negative Travel Limit
Type: Axis Parameter Register
RMC70 Address: %MDn.93, where n = 12 + the axis number
RMC150 Address: %MDn.93, where n = 24 + the axis number
System Tag: _Axis[n].NegTravelLimit, where n is the axis number
How to Find: Axes Parameters Pane, Setup tab: Primary Control Setup
Data Type: REAL
Units: pu
Range: any
Default Value: 0
Description
The Negative Travel Limit and the Positive Travel Limit specify the position boundaries in
which the axis is allowed to operate. The Positive Travel Limit must be greater than or
equal to the Negative Travel Limit. These limits are not available on Rotary axes.
In Closed Loop Control
If the Target Position exceeds the Positive Travel Limit, the Positive Overtravel error bit
will be set. If the Target Position is less than the Negative Travel Limit, the Negative
Overtravel error bit will be set. While the axis is in an overtravel condition, motion
commands that move the axis toward the valid range will be accepted, even if they don't
move the axis entirely into the valid range.
In Open Loop Control
If the Actual Position exceeds the Positive Travel Limit, the Positive Overtravel error bit
will be set. If the Actual Position is less than the Negative Travel Limit, the Negative
Overtravel error bit will be set. While the axis is in an overtravel condition, motion
commands that move the axis toward the valid range will be accepted, even if they don't
move the axis entirely into the valid range.
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