3M C3266PW User's Guide download pdf (Page 44)

44 3M™ Multi-Touch Chassis Display User Guide

3M Touch Systems, Inc. Proprietary Information – TSD-39373B

Calibrate

Syntax: <SOH>CX<CR>

Response: <SOH>1<CR> Valid point response.

A Valid Point Response (‘1’) signifies that a touch coordinate was detected and is in

range of the expected screen target area. Two valid point responses indicate successful

calibration.

<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.

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3M C3266PW User's Guide Page 44