User's Manual

File : CS-SUP-MUTI-WTHERMSPETEC-E02.sxw
2 INFORMATION RELATIVE TO THE PROBES ASSOCIATED WITH THE
WAVETHERM MODULES
2.1 DALLAS PROBES
2.1.1 CODING OF TEMPERATURES FOR THE DALLAS PROBE TYPE DS18B20
These probes have a resolution of 12 bits and their value is coded on two bytes (MSB first)
Negative values are expressed in two's complements with addition of a sign.
Remark: The hexadecimal value 0x4FFF indicates the absence of a probe, or a connection error between
the module and the probe.
 Some temperature values:
Temperature Binary value (MSB First) Hexadecimal value
+125°C 0000 0111 1101 0000 0x07D0
+85°C 0000 0101 0101 0000 0x0550
+25°C 0000 0001 1001 0000 0x0190
0°C 0000 0000 0000 0000 0x0000
-10.125°C 1111 1111 0101 1110 0xFF5E
-55°C 1111 1100 1001 0000 0xFC90
2.1.2 PROBE ID
The probe ID corresponds to a unique code attributed to each DALLAS temperature probe in the factory.
This code is composed of 8 bytes defined as follows:
MSByte LSByte
1 byte 6 bytes 1 byte
Family Code Serial n° (48 bits) CRC Code
The family code is used to distinguish between the probes used:
Probe DS18S20 : 0x10
Probe DS18B20 : 0x28
2.1.3 SETTING OF THE PROBE COEFFICIENT PARAMETERS
The precision of DALLAS probes is indicated by the manufacturer as ±0.5°C (-10°C to +85°C) and requires
no calibration before use.
However, it is possible to improve this precision if the user wishes to calibrate the probe. In this case, the
WaveTherm module contains a 32-byte memory zone for storage of transfer coefficients after calibration.
Management of this memory zone is described further in chapter 5.2.
WaveTherm module technical specifications page 13 of 31