6
READING EXAMPLE
Example of MODBUS RTU command for reading the temperature (float value) T = 24.270019 °C from the register 0x19:
Device EE210; slave ID 242 [F2 in Hex]
Reference document, chapter 6.3: http://www.modbus.org/docs/Modbus_Application_Protocol_V1_1b.pdf
Request [Hex]: F2 03 00 19 00 02 01 0F
Modbus ID
address
Function
code
Starting
address Hi
Starting
address Lo
No. of
register Hi
No. of
register Lo
CRC
Request
[Hex]:
F2
03
00
19
00
02
01
0F
Response [Hex]: F2 03 04 29 00 41 C2 80 A1
Modbus ID
address
Function
code
Byte count
Register 1
value Hi
Register 1
value Lo
Register 2
value Hi
Register 2
value Lo
CRC
Response
[Hex]:
F2
03
04
29
00
41
C2
80
A1
For decoding of float values (stored according standard IEEE754), please refer to AN0103, chapter 7.
Example of decoding:
Response [Hex]:
Value in decimal
Byte 1
(Register 2 - Hi)
Byte 2
(Register 2 – Lo)
Byte 3
(Register 1 - Hi)
Byte 4
(Register 1 - Lo)
41
C2
29
00
24,270019
TECHNICAL DATA
(Modification rights reserved)
Measured Values
Relative Humidity (RH)
Working range
0...100 %RH
RH accuracy
1)
(incl. hysteresis, non-linearity and repeatability)
Type T1 (wall), T2 (duct):
-15...40
°C
(5...104 °F)
≤90 %RH
±(1.3 + 0.003*measured value) %RH
-15...40
°C
(5...104 °F)
>90 %RH
±2.3 %RH
-40...60
°C
(-40...140 °F)
±(1.5 + 0.015*measured value) %RH
Type T3 (remote):
at 20 °C
(68 °F)
±2.5 %RH
Type T13 (outdoor):
-15...40
°C
(5...104 °F)
≤90 %RH
±(1.6 + 0.005*measured value) %RH
-15...40
°C
(5...104 °F)
≥90 %RH
±3 %RH
-40...60
°C
(0...140 °F)
±(2.3 + 0.008*measured value) %RH
Temperature (T)
T accuracy
Type T1, T2
Type T3
Type T13
1) Traceable to intern. standards, administrated by NIST, PTB, BEV,... The accuracy statement includes the uncertainty of the factory calibration with an enhancement factor k=2 (2-times
standard deviation). The accuracy was calculated in accordance with EA-4/02 and with regard to GUM (Guide to the Expression of Uncertainty in Measurement).
For Type T13: at 24 V DC and RL=250 for A6 versions.
± ∆T [°C]
T [°C]
T [°C]
± ∆T [°C]
± ∆T [°C]
T [°C]
