Manual

Linearity Correction 9-3
Example
The following sequence of commands sets a correction grid spacing of 4000 microsteps in
each axis and then establishes X and Y corrections for each grid intersection up to 8000
microsteps in each axis (i.e. at 0, at 4000, and at 8000 microsteps in each axis):
CR -1, -1, 4000,4000;
CR 0, 0, 2, 3.5; CR 1, 0, -1, 4; CR 2, 0, -2, 6;
CR 0, 1, 4, 7.75; CR 1, 1, -2, 6; CR 2, 1, 7, 6.5;
CR 0, 2, 5, 6; CR 1, 2, -4, 6; CR 2, 2, 6, 5;
Note: Some of the corrections are not whole numbers of microsteps (e.g. 7.75). At these
grid locations the System adds this non-integer number of microsteps, but then it
rounds to the nearest microstep.
Disabling the Correction Mechanism
As a further special case the linearity correction mechanism can be completely disabled by
specifying both the X and Y grid spacings equal to 0. In other words, to disable linearity
correction, send the following: "CR -1, -1, 0, 0;". The values in the table are unaffected.
To re-enable correction, send another CR with the desired values of X and Y grid size.
Non-Volatile Storage
The linearity correction information is stored in the Automove System's non-volatile
memory. This means that the System "remembers" the information even when the power is
turned off.
Be sure to flip the backpanel Write Protect switch down (or up in a gantry-mount machine)
before executing any CR command. If you don't, the CR command will give an error.
Outputting To The Host
The host computer can determine the current correction grid spacing and the values stored in
the correction table by sending the OR ("Output Correction") command. The syntax is:
OR <x index>, <y index>
where <x index> and <y index> are interpreted as in the CR command. In other words, if
<x index> and <y index> are in the range 0 through 19 then the Automove System sends
the current values of X and Y correction, separated by a comma. The values are in micro-
steps, in the range -128.0000 through 127.0000.
If <x index> and <y index> are both -1 then the Automove System outputs the X and Y
correction grid spacing, separated by a comma. The values are in microsteps, and are either
0 (if the mechanism is disabled) or are in the range 0.0313 through 32767.0000.