Section 7
Parameter Settings
58
FT742-SM (RS422 & RS485) Sensors
– User Manual
7.4.15 HT.1: Set or Query General Heater Settings
Command
Parameter
HT (enable/ disable)
Command
Syntax
SET Sensor:
$<listenerID>,HT<tsp>*<checksum><cr><lf>
$aa,HTxx*hh<cr><lf>
QUERY Sensor:
$<listenerID>,HT?*<checksum><cr><lf>
$aa,HT?*hh<cr><lf>
Sensor output:
$<talkerID>,HT=<tsp>,<%>,<temp>*<checksum><cr><lf>
$aa,HT=xx,xx,
xx*hh<cr><lf>
Parameters
<tsp>
00-55
Heater control circuit set point temperature (degrees Celsius)
99
Disables the heater (factory default setting)
<%>
00-99
Read only parameter that returns the % of full scale heater current
limit
0% (heater off) to 99% (heater fully on)
<temp>
-99 to +99
Read only parameter that returns the current internal temperature of
the sensor, In
⁰
C, in range 00 to ±99
⁰
C
Examples
Example 1
Set the sensor set point temperature to 5
C. Verify that the command has been accepted.
Message
Comment
$01,HT05*//<cr><lf>
Set heater set point temp
$01,HT?*//<cr><lf>
Query heater setting
$WI,HT=05,00,+24*3B<cr><lf>
Sensor response
Example 2
Turn off the sensor heater. Verify that the command has been accepted.
Message
Comment
$01,HT99*//<cr><lf>
Disable heater
$01,HT?*//<cr><lf>
Query heater setting
$WI,HT=99,00,+24*3E<cr><lf>
Sensor response
Description
Use the HT command to set the sensor heater parameters, including switching the heater
on or off and configuring the heater set point. It is possible to query the sensor’s internal
temperature. It is also possible to query the duty cycle of the heater, which specifies the
percentage of the current being drawn by the heaters.
Note: Modifications to the heater current maximum limit are not permitted on the FT742-SM
range. Contact FT technical support for further information.
The heater requires a minimum supply of 9VDC in order to activate. Contact FT
Technologies for further information about heater power specifications and management.
