Delta RMC101 - Manual (Page 217)

Position/Pressure Control 4.12
Controller Features 4-31
Three Basic Modes of Operation
There are three basic modes that must be understood in order to control pressure or force:
• Position Control Mode:
In this mode, the position axis is entirely controlling the drive output. The status fields of the
pressure axis will still be updated, but the pressure axis will have no affect on the position drive
output. Position axes which do not have assigned pressure axis will always operate in this
mode.
• Pressure Monitoring Mode:
In this mode, the position axis is controlling the drive output, but is monitoring the pressure (or
force) during the move. As soon as the pressure reaches a minimum pressure threshold (given
by the Pressure Set A field), the axis will enter Pressure Regulating Mode. To enter this mode, a
move command (either Go (G) or Relative Move (J) ) with the Monitor Pressure bit set in the
Mode word must be issued.
• Pressure Regulating Mode:
In this mode, the pressure axis is controlling the pressure (or force). The position of the axis will
have no effect on the control of the axis except in the following cases:
o
If the Actual Position of the axis moves outside the Extend or Retract limits, the axis
goes into open loop mode with the Null Drive output. The axis does not return to
pressure monitoring mode unless the pressure falls below another pressure threshold
(given by the Pressure Set B field).
o
If the Actual Position reaches the commanded position, the Target Pressure will
decrease in order to prevent the Actual Position from exceeding the Command Position.
This assumes that the axis is compressing something that may spring back if the
exerted force is decreased. To get the Target to increase, re-issue the Set Pressure
Command.
The axis may leave pressure regulating mode and return to Position Control by giving a move
command without the Monitor Pressure Mode bit set.
A typical position/pressure application uses the above modes in the following order:
1. A move is made in position control mode to the starting position.
2. A move is made in the direction of increasing pressure with the monitor pressure bit set
(pressure monitoring mode).
3. When the pressure reaches Pressure Set A, the axis enters pressure regulating mode. Pressure
can now be controlled.
4. To exit pressure control, a move is made with the Monitor Pressure bit cleared.
To perform position/pressure control on your system:
• Set up the RMC100
See Position/Pressure Setup for a step-by-step illustrated procedure on how to set up the
RMC100 for position/pressure control. Included are instructions for using the Step Table and the
commands required for position/pressure control.
• Tune the system