Difference between revisions of "AXY:MC-Basic:axis.POSITIONERROR"
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Revision as of 08:46, 22 May 2014
This property returns the position following error, which is the difference between position command and the position feedback. The calculation takes the SERCOS delay into account, such that the position feedback is subtracted from the command issued two cycles previously. It is calculated every sample time and compared to maximum position error (PEMAX). If it exceeds the value of PEMAX, the axis is brought to an immediate stop. If the axis is at rest when the error is detected, the drive is disabled.
The following error is at a minimum when the drive is properly tuned. An additional servo delay is added when microinterpolation is enabled on the CDHD drive. In this case, the position error calculated by the softMC is slightly larger, but the motion is smoother.
The calculation takes into account the position error delay, such that the position feedback is subtracted from the command issued a number of cycles previously, as defined in the POSITIONERRORDELAY property.
Short form
<axis>.PE
Syntax
?<axis>.PositionError
Availability
All versions
Type
Double
Range
± MaxDouble
Units
User axis position units, as given by <axis>.POSITIONFACTOR.
Default
0
Scope
Task or Terminal
Limitations
Read only
Examples
Pos_err = Xaxis.PE