Delta RMC151 - Manual (Page 820)

RMC70/150 and RMCTools User Manual
• Negative (2)
1
• Bidirectional (3)
1
1
Note: The Negative and Bidirectional options require
firmware 3.44.0 or newer.
Description
This command enables or disables Pressure/Force Limit, and specifies the direction of the
limiting. Pressure/Force Limit limits the Actual Pressure or Force during a position or
velocity move. Pressure/Force Limit is useful in applications that require moving to a
position while not exceeding a certain pressure or force during the move.
In Pressure/Force Limit, the Target Pressure/Force is the value at which the Actual
Pressure or Force will be limited. The axis position or velocity can be controlled normally
as long as the Actual Pressure or Force does not approach the limit. As the Actual
Pressure or Force approaches the threshold, the RMC will limit the motion so that the
pressure/force limit is not exceeded. For more details, see the Pressure/Force Limit
Algorithm topic.
Direction
The direction of the force limiting is specified by choosing the Positive, Negative, or
Bidirectional parameters.
• Positive
The pressure/force will be limited to the Target Pressure/Force, in the direction of
increasing pressure/force.
• Negative
The pressure/force will be limited to the negative value of the Target Pressure/Force,
in the direction of decreasing pressure/force. The Target Pressure/Force itself should
be a positive value, but the limit will be applied to the negative value.
• Bidirectional
The pressure/force will be limited in both directions of motion, to the positive Target
Pressure/Force in the direction of increasing pressure/force, and to the negative
Target Pressure/Force in the direction of decreasing pressure/force. The Target
Pressure/Force itself should be a positive value. If different limit values are required in
each direction, then the user must keep track of the direction of motion and set the
Target Pressure/Force appropriately.
Limitations
Pressure Limit cannot be used in Direct Output. To issue the Set Pressure/Force Limit
Mode command, the Direct Output Status bit must be off. To turn off the Direct Output
Status bit, put the axis in Open Loop or Closed Loop control.
If the axis is in pressure/force control, then pressure/force limit will be ignored. However,
the Set Pressure/Force Limit Mode (40) command will still set and clear the
Pressure/Force Limit Enabled status bit. If the axis exits pressure/force control,
pressure/force limit will be enabled if the Pressure/Force Limit Enabled status bit is set.
Note:
Pressure/force limit may affect motion even when the Actual Pressure/Force is well below the
limit. In order to achieve precise motion when pressure/force is not important, do not set the
pressure/force limit mode to Enabled. Enable pressure/force limit only after the pressure/force
has increased close to the point where the pressure/force is to be limited.
Another option is to use pressure/force control, which will not affect the position motion.
Usage Details
800 Delta Computer Systems, Inc.