Command pressure/force, Target pressure/force, Actual pressure/force – Delta RMC101 User Manual
Page 885: D.3 pressure/force status fields, D.3.1 command pressure/force, D.3.2 target pressure/force, D.3.3 actual pressure/force
Appendix D: Status Field Reference
D-23
For DelayMS (D) and DelayTicks (d) link types, this field displays the number of delay units left (in
either counter ticks or milliseconds).
D.3 Pressure/Force Status Fields
D.3.1 Command Pressure/Force
This field holds the requested pressure or force. It is set to the Command Value of the Set
Pressure command.
D.3.2 Target Pressure/Force
Note:
In this topic, the word pressure is used. If you are using differential force, you can replace
every occurrence of pressure with force.
The Target Pressure is the calculated instantaneous ideal pressure of the axis. The Target
Pressure is calculated every control loop by the target generator state machine of the RMC. The
PID routine uses the difference between the Target Pressure and the Actual Pressure as its input
to compute any required corrective drive.
During a move the transition of the Target Pressure toward the Command Pressure will be the
perfect profile for the Actual Pressure to follow.
Why Bother?
Knowing the relationship between the Target Pressure and Actual Pressure is key to tuning the
axis. The main goal in tuning the axis is to minimize the error between the Target and Actual
Pressures. The plot function is a very useful visual aid in tuning the axis.
D.3.3 Actual Pressure/Force
This field gives the instantaneous pressure or force of this axis. This value is updated every
control loop (1 or 2 milliseconds, depending on the module).
For single-ended pressure axes, this field is calculated as follows:
For differential force axes, this field is calculated as follows: