File : CS-SUP-MUTI-WTHERMAPP-E01.sxw
contents of RECEIVED_FRAME response
Data Field (max : 152 bytes)
Acknowledgement
of the applicative
command
Status de l'étalonnage
Reference resistance
A
(LSB First)
Reference resistance
B
(LSB First)
1 byte
1 byte
4 bytes
4 bytes
0x88
0x00
: calibration OK
0xFF
: calibration error
Resistances A and B are restored in the 32-bits floating numbers format (LSB first). Format described in
chapter 5.2.
5.2.3 Setting of probe coefficient parameters
The PT100 and PT1000 probes have a coefficient providing a linear temperature response.
Remark :
The European standard EN60751 relative to probes defines 3 coefficients A,B and C used in
the calculation of the relationship : resistance = f (temperature).
In the -200 to 0°C range :
R = R0[1+At + Bt
2
+ C(t – 100°C)t
3
)
in the -0°C to 850°C range:
R = R0(1+At + Bt
2
)
R0 : Resistance at 0°C
A, B and C: transfer coefficients
As the WaveTherm module operating mode consists of measuring the probe resistance and then calculating
the temperature, it requires coefficients in order to calculate the relationship between these values:
temperature = f (resistance)
and not
resistance = f (temperature).
The relationship T = f(R) must therefore be calculated according to the relationship provided in standard
EN60751.
The following polynomial is used:
T = C
7
.R
7
+ C
6
.R
6
+ C
5
.R
5
+ C
4
.R
4
+ C
3
.R
3
+ C
2
.R
2
+ C
1
.R + C
0
where
C
7
, C
6
, C
5
, C
4
, C
3
, C
2
, C
1
, and C
0
are the parameters to be transferred to the radio module
The coefficients to be transferred to the radio module are based on the coefficients A,B and C (given by the
manufacturer of the PT100 or PT1000 probes) in a mathematical formula. When required, CORONIS is able
to provide a utility enabling calculation of these coefficients. There are 8 in total (coeff A to H).
They are managed with standard internal parameters read and write commands. (see chapter 6.2).
WaveTherm modules – application handbook
page 19 of 65
