3M™ Multi-Touch Chassis Display User Guide
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3M Touch Systems, Inc. Proprietary Information -- 37732v04
<SOH>
0
<CR> Invalid point response
An Invalid Point Response (‘0’) is returned if the touch coordinate is out of range. If
either calibration point is invalid, the touch coordinates are discarded and the calibration
points remain unchanged from their previous values.
<SOH>
2
<CR> Invalid point response
An Invalid Point Response (‘2’) is returned if the user did not touch the target long
enough to provide an accurate point.
Description:
Initiates an interactive 2-point calibration.
During the calibration process, you define the active area of the touch sensor by mapping
locations to an absolute X/Y coordinate system. You touch two
target areas
on the
sensor. Touching the target areas sends the X/Y coordinates for those touch points to the
controller. The controller calculates all other touch points based on these two points.
The Calibrate command sets the calibration targets (points) 12½ percent inward from the
corner of the video image. Setting the targets inward makes the calibration process easier
and more accurate.
It also establishes screen orientation.
Calibrate Procedure
To use the CX command:
1.
Enter the Calibrate (CX) command. The controller sends an initial acknowledgment
of <SOH>0<CR>.
2.
Touch the sensor at a lower left target, which is located 12.5% (1/8) in from the
corner of the video image. The controller returns an acknowledgment of
<SOH>1<CR>. This is a positive response. If you receive a negative response
<SOH>0<CR>, you can cancel the calibration by issuing a Reset command and then
start over again.
3.
Touch the sensor at an upper right target, which is located 12.5% (1/8) in from the
corner of the video image. The controller returns an acknowledgment of
<SOH>1<CR>. This is a positive response. If you receive a negative response, you
must start over again.
Touching the two valid calibration points results in a successful calibration. If either
calibration point is invalid, the calibration fails. The PX controller restores the previous
calibration values. If Calibrate fails, repeat the CX process.
