Target Position

Type:	Axis Status Register
Address:	RMC75: %MDn.53, where n = 8 + the axis number RMC150: %MDn.53, where n = 8 + the axis number RMC200: %MDn.400, where n = 256 + the axis number
System Tag:	_Axis[n ].TarPos, where n is the axis number
How to Find:	Axes Status Registers Pane, Basic tab
Data Type:	REAL
Units:	pu

Description

When the axis is in Closed Loop control, the Target Position is the calculated instantaneous ideal position for the axis. The Target Position is calculated every loop by the target generator of the RMC. During a move the path of the Target Position toward the Command Position will be the perfect profile for the Actual Position to follow.

The control algorithm uses the difference between the Target Position and the Actual Position to compute any required corrective Control Output.

When an axis is stopped, the Target Position should be the same as the Command Position unless an error or halt has occurred. When an axis is in Open Loop control, the Target Position is set to the Actual Position.

Why Bother?

Knowing the relationship between the Target Position and Actual Position is key to tuning the axis. The main goal in tuning the axis is to minimize the error between the Target and Actual Positions. The plot function is a very useful visual aid in tuning the axis.