Tritex 1 Installation and Setup
80
09/27/12
PN: 27666
Exlar Corporation
Rev. M
952-500-6200M
Position Limits
Position Limits are software monitored travel limits with special features for control outside of
the travel limits.
The limits can be enabled individually for each direction during all modes of motion. The
controller looks ahead to anticipate when/if the position limit will be hit based on the current
velocity at approximately a 2msec scan rate. If it is determined the limit will be reached the
control decelerates using the acceleration/deceleration rate for the active mode. Once the
commanded position is outside of the position limit range the Velocity, Foldback Current and
Seating Current parameters take effect. The motion control while outside of the position limits
operates in a special mode to limit velocity and the current. If the velocity is set to zero, motion
will stop near the limit position, if is non zero the motor will ramp to the limit velocity, without
stopping, looking for a hard-stop. When the hard stop is hit the seating current will be produced
for the specified time and then the current will be switched to the foldback current value. During
this Position Limit mode of operation the following error does not build up when a hard stop is
reached, the following error is controlled to maintain the desired current limit. The limits are
direction sensitive, meaning that velocity and current are only limited in the direction of the
active position limit, any motion commanded in the opposite direction will operate normally.
Exception: If the mode of operation is Analog Torque or Host Current Mode the velocity limit will
not be in effect, the seat and foldback current limits are active.
Note: Position Limits are only active after a home has been completed.
Normal
Motion
Limit
Velocity
Hard-stop
Positive Position
Limit
Running
current
Current
Seating
current
Seating time
Foldback
Current
Velocity
