APG IRU-3000 user manual User Manual
Page 14

IRU-2xx4/3xx4
Rev. A2, 11/08
14
Automation Products Group, Inc.
APG...Providing tailored solutions for measurement applications
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CALIBRATION
Calibration The IRU-2XX4/3XX4 must be calibrated if a familiar reading is
desired. The software is designed so that a calibration factor of 1000 will yield
units that represent inches, feet and meters. Variations of the speed of sound in
different atmospheres may yield readings which slightly differ from actual
measured values. If this is unacceptable, vary the Calibration factor to “dial in”
the exact number desired.
Acceptable values for this parameter range from 0100 to 1999
If a certain distance to a target is known and the sensor is not outputting the
desired reading, use the following formula to obtain the desired reading.
New Calibration Factor = (Desired Distance Reading x Old Calibration Factor) /
Sensor Distance Reading.
Example: Suppose a target is 5.50 feet from the face of the sensor. The sensor
has a calibration factor of 1000 and is yields a Distance Reading of 5.65 ft.
Calculate the new Calibration Factor by:
New Calibration Factor = (5.50 x 1000) / 5.65 = 0973.
To read the calibration factor in a sensor, use the command structure:
Send
Receive
AAh
Start Byte
66h
Start Byte
01h,
Sensor Number
01h
Sensor Number
0Bh
Command
0Bh
Command
00h
Data (not used)
03h
Calibration (High Byte)
00h
Data (not used)
E8h
Calibration (Low Byte)
55h
End Byte
##h
NA
99h
Stop Byte
To change the calibration factor in a sensor, use the command structure;
Send
AAh
Start Byte
01h,
Sensor Number
0Ch
Command
03h
Data (not used)
0973 D = 3CD
CDh
Data (not used)
55h
End Byte