File : CS-SUP-MUTI-WTHERMAPP-E01.sxw
7.2 READING THE CURRENT VALUE OF THE TEMPERATURE SENSORS
The WaveTherm module has the possibility to read the current temperature when the sensors are wired, and
initialized. If not the input relative to the sensor not wired (or initialized) returns the following values :
WaveTherm – DALLAS :
0x4FFF
WaveTherm – PT100 :
0xFFFFFFFF
WaveTherm – PT1000 :
0xFFFFFFFF
In addition, this command returns the
Operating Mode
, and
Application Status
bytes.
7.2.1 Information concerning precision
Compatibility : - WaveTherm – PT100
- WaveTherm – PT1000
Temperature measurement may be started with one of several precision levels (0 to 3). In general, precision
level 0 is sufficient. The other precision levels are used in difficult environments.
The aim of these precision levels is to compensate for measurement errors induced by the 50 Hz frequency.
In practice, this precision is increased by increasing the number of measurement sequences for the same
temperature. Each measurement sequence is offset in relation to the previous sequence by 50Hz.
The precision levels may be described as follows,
Precision = 0x00 :
normal precision
(fastest measurement)
Precision = 0x01 :
high precision
Precision = 0x02 :
very high precision
Precision = 0x03 :
maximum precision
(slowest measurement)
Remark: Above all, the primary function is to preserve measurement precision, even in an
environment with considerable interference, and not to improve the measurement precision of the
probe itself.
Furthermore, the higher the precision, the higher the module power consumption. It is therefore
important to find the best possible consumption/precision compromise.
The choice of the precision level is coded in the command used to read the current value of the temperature
sensors.
7.2.2 Description of the commands to be used
Applicative Command Description
0x01
Request to read the current temperature values
0x81
Response to the request to read the current temperature values
WaveTherm modules – application handbook
page 34 of 65
