Section 6
Parameter Settings
53
FT742-SM (RS422 & RS485) Sensors
– User Manual
7.4.20 UC.1: General User Calibration Settings
Command
Parameter
UC (enable/ disable)
Command
Syntax
SET Sensor:
$<listenerID>,UC<table>*<checksum><cr><lf>
$aa,UCx*hh<cr><lf>
QUERY Sensor:
$<listenerID>,UC?*<checksum><cr><lf>
$aa,UC?*hh<cr><lf>
Sensor output:
$<talkerID>,UC=<entries>,<table>,<UCRAMChecksum
>, <UCFlashChecksum>*<checksum><cr><lf>
$aa,UC=nn,x,yyyy,zzzz*hh<cr><lf>
Parameters
<
table
>
E
User Calibration Table enabled
D
User Calibration Table disabled (Factory Default Setting)
<entries>
nn
Number of calibrated table entries
<UCRAMChecksum>
yyyy
User calibration table RAM copy checksum
<UCFlashChecksum>
zzzz
Saved user calibration table Flash copy checksum
Examples
Example 1
Enable the user calibration table and verify new setting
Message
Comment
$01,UCE*7E<cr><lf>
Enable calibration table
$01,UC?*04<cr><lf>
Query user calibration table status
$WI,UC=55,E,5174,5174*70<cr><lf>
Typical sensor response
Description
Use the UC command to enable or disable the implementation of the user calibration table
for calibrating wind speed readings.
The four-digit user calibration table checksum is calculated by summing all table
entries over the number of table rows present. The least significant 4 digits of the
resulting sum are retained as the table checksum. The user-defined text string is not
included in the checksum. Each xx.xx speed value is treated as an integer by ignoring
the decimal point. For example, the table row:
15.00, 14.97 is summed as 1500 + 1497 = 2997. A table sum of 55174 results in the
checksum 5174.
If the user calibration table has not been loaded, the number of calibrated table entries
(nn) will be 00 and the saved user calibration table Flash copy checksum (zzzz) will be
5535.
When the User Calibration facility is
enabled, the uncorrected wind speed
indication of the sensor is calibrated
according to the stored calibration
records, using linear interpolation.
