Rockwell Automation GMLC Reference Manual - Manual (Page 517)

Publication GMLC-5.2 - November 1999
480 Motion Variables
The accuracy of the registration position value, saved as a result of a
registration event, is a function of the delay in recognizing the specified
transition (1 µs) and the speed of the axis during this time. The
uncertainty in the registration position is the distance traveled by the axis
during 1 µS (0.000001 second) as shown by the following equation:
Use the formula above to calculate the maximum registration position
error for the expected axis speed. Alternatively, you can calculate the
maximum axis speed for a specified registration accuracy by re-arranging
this formula as shown in the following equation:
Soft Registration Position
Whenever an axis registration event occurs, the actual position of the axis
is latched in hardware and is then available as the Registration_Position
variable of the axis. In addition to this hard registration, the actual
positions of all physical and virtual axes, as well as the command position
of the imaginary axis, are also stored in the appropriate Soft_Reg_Posx.x
variables when the registration event occurs. This soft registration stores
the positions of all axes as sampled at the beginning of the first servo
update following a registration event on any axis.
In the Tag Explorer, select both Axis System Variables and the desired
axis, then select Soft_Reg_Posx.x in the Tag Window. See Watch Control,
with Arm Registration selected, in this manual for information on setting
up registration events.
Seconds 000001 . 0
Second
Units Position
Speed Axis y Uncertaint
×




=
[ ]
Seconds 000001 . 0
Units Position Accuracy Desired
Second
Units Position
Speed Maximum
=



