3M Systems EX II 3700SP - Manual (Page 19)

3M™ MicroTouch™ Controller SX112 Reference Guide 19
3M Touch Systems, Inc. Proprietary Information
*The coordinates are in video terms, with the origin (0, 0) in the upper left corner of the sensor. Examples from the
controller’s perspective, however, place the origin at the lower left corner of the sensor (numbers in brackets). The
controller outputs 0 to 64K on both axes independent of display screen resolution.
Calibrate Extended Procedure
To use the CX command:
1. Enter the Calibrate Extended (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 SX112 controller restores the
previous calibration values. If the Calibrate Extended failed, repeat the CX process.
Response: <SOH>1<CR> Positive response.
Indicates that the controller received a valid touch coordinate (point) when the target was
touched. Two valid touch points indicate a successful calibration.
<SOH>0<CR> Negative response
Indicates that the touch point is out of range of the expected target area. If you receive a
negative response, you must start over again.
No Response
Indicates that you did not touch the target long enough to provide an accurate calibration
point.
(0, 767) [0, 1024]* [1024, 1024]*
Upper Right Calibration Target
X = 1023 – (1024 x 1/8) = 1023 – 128 = 895
Y = 0 + (768 x 1/8) = 0 + 96 = 96
Lower Left Calibration Target
X = 0 + (1024 x 1/8) = 0 + 128 = 128
Y = 767 - (768 x 1/8) = 767 - 96 = 671
(0, 0) [0, 0]* ( 1023, 0) [1024, 0]*
(128, 671)
(895, 96)