RTC
®
5 PC Interface Board
Rev. 1.9 e
10 Commands And Functions
428
innovators for industry
Ctrl Command set_fly_tracking_error
Function
activates or deactivates tracking error compensation of encoder values for Processing-on-
the-fly applications.
Call
set_fly_tracking_error( TrackingErrorX, TrackingErrorY )
Parameters
TrackingErrorX
,
TrackingErrorY
Tracking error in units of [10
µ
s] for each axis (signed 32-bit values)
allowable range: [0 … 65535], excessive bits are ignored.
Comments
• Tracking error compensation is a first-approximation correction:
EC = E + ( E – EP ) *
TrackingError
,
whereby E is the current encoder value, EP is that of the previous cycle and EC is the
compensated encoder value (used for Processing-on-the-fly correction).
• To avoid step-like galvanometer movements, the used encoders should have a suffi-
ciently high resolution (counts per 10
µ
s cycle).
• If
TrackingErrorX,Y
= 0 (initialization value), then compensation will be switched off.
• The commands
,
still use the original,
uncorrected encoder values.
• This compensation is practical only for linear motions (
), not for
rotary motions (
). For the latter,
TrackingErrorX,Y
should be set to 0.
• If the encoders get reset via the start trigger (
output value of the first 10
µ
s cycle might be incorrect to an unforeseen extent. Resets
via the
commands automatically wait internally for an empty
cycle.
• This compensation only functions for Processing-on-the-fly applications with encoders,
but not with position signals via the McBSP interface.
RTC
®
4
RTC
®
5 new command
Version info
Available beginning with version DLL 533, OUT 534, RBF 524
