Section 6
Parameter Settings
36
FT742-SM (RS422 & RS485) Sensors
– User Manual
7.4.3
CU: Set or Query the Continuous Update Setting
Command
Parameter
CU
Command
Syntax
SET Sensor:
$<listenerID>,CU<cont.update>,<interval>*<checksum>
<cr> <lf>
$aa,CUcxxxxx*hh<cr><lf>
QUERY Sensor:
$<listenerID>,CU?*<checksum><cr><lf>
$aa,CU?*hh<cr><lf>
Sensor Output:
$<talkerID>,CU=<cont.update>,<interval>*<checksum><
cr> <lf>
$aa,CU=c,xxxxx*hh<cr><lf>
Parameters
<continuous update>
E
Enabled
D
Disabled (Factory Default Setting)
<interval>
1 to 59999
interval, in 0.1s increments, between outputs in continuous mode
Examples
Example 1
Set the sensor to output readings automatically every 10 seconds. Verify that the command
has been accepted.
Message
Comment
$01,CUE00100*//<cr><lf>
Enable CU mode, rate = 0.1Hz
Example 2
Disable the continuous updating. Verify that the command has been accepted.
Message
Comment
$01,CUD*//<cr><lf>
Disable CU mode
$01,CU?*//<cr><lf>
Query CU mode setting
$WI,CU=D,00100*40<cr><lf>
Sensor response
Description
Use the CU command to enable or disable the continuous update mode of operation. When
continuous update is enabled, the sensor will output wind velocity readings at a rate
determined by the <interval> setting.
Each time the continuous update mode is enabled, the required <interval> setting must be
sent (even if this has been sent to the sensor previously). When the continuous update
mode is enabled, if the sensor is switched-off, when power is reapplied the sensor will
automatically resume outputting readings.
Once the sensor has been put into continuous update mode then it becomes a talker only
and will not respond to any further commands. To be able to send commands again the
continuous mode must be disabled. To achieve this, the CUD (disable continuous update
mode) command must be sent within the first four seconds of the power being applied to the
sensor. It is possible to modify the four second delay period on the FT742-SM sensor,
contact FT Technologies for further information.
Note: CU mode operation typically uses RS422 communication. For CU mode operation in
RS485, software version 7.4 and above will be required.
WARNING:
Do not use the continuous update mode if
there are other talkers connected to the data bus.
Only one active talker is allowed on the data bus at
any one time otherwise bus contention will occur
