File : CS-SUP-MUTI-WTHERMAPP-E01.sxw
7.6.2 Precision level of the measurement
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 precision level in datalogging mode is selected by configuring the parameter 0x0C.
7.6.3 Format of the temperature information
The format depend of the type of the module used, and is strictly identical to the format when reading the
current value of the temperature (see chapter 5.1.1, and 5.2).
➢
Example for a WaveTherm – DALLAS :
MSB
LSB
MSB
LSB
Most Significant Byte
Least Significant Byte
b7
b6
b5
b4
b3
b2
b1
b0
b7
b6
b5
b4
b3
b2
b1
b0
S
S
S
S
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
2
-1
2
-2
2
-3
2
-4
Bits [b7:b3] : sign bits.
Example :
The high threshold parameter is set to default value 0x01A0
According to the format, High Threshold
= 2
4
+ 2
3
+ 2
1
= 26 °C
WaveTherm modules – application handbook
page 57 of 65
