E+E Elektronik Modbus MOP301, Руководство пользователя

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User Manual MOP301 Digital Moisture in Oil Immersion Probe
5.6 Modbus RTU Examples
The MOP301’s Modbus address is 70 [0x46].
Please refer to
■
MODBUS APPLICATION PROTOCOL SPECIFICATION V1.1b3, chapter 6:
www.modbus.org/docs/Modbus_Application_Protocol_V1_1b3.pdf
■
E+E Application Note Modbus AN0103 (available at www.epluse.com/mop301 )
Read the temperature (FLOAT32) T = 26.66048812866211 °C from register address 0x3EA :
Master (e.g. PLC)
MOP301
Request [Hex]:
Modbus
address
Function
code
Starting
address Hi
Starting
address Lo
Qty. of
registers Hi
Qty. of
registers Lo
CRC
46 03 03 EA 00 02 EA CC
Response [Hex]:
Modbus
address
Function
code
Byte
count
Register 1
value Hi
Register 1
value Lo
Register 2
value Hi
Register 2
value Lo
CRC
46 03 04 48 AE 41 D5 4A B9
Floating point values are decoded according to IEEE754, refer to the example at the end of this chapter.
Read register from custom modbus map
address 0x0BB8-0x0BB9, unconfigured
Request [Hex]:
Modbus
address
Function
code
Starting
address Hi
Starting
address Lo
Qty. of
registers Hi
Qty. of
registers Lo
CRC
46 03 0B B8 00 02 49 7D
Response [Hex]:
Modbus
address
Function
code
Byte
count
Register 1
value Hi
Register 1
value Lo
Register 2
value Hi
Register 2
value Lo
CRC
46 03 04 FF FF FF FF CC A3
Mapping custom Modbus map
assign T (register address 0xEA) and aw (register address 0x46E) to the custom Modbus map, starting
address 0xBB8
Request [Hex]:
Modbus
address
Function
code
Starting
address Hi
Starting
address Lo
Qty. of
registers Hi
Qty. of
registers Lo
Byte
count
46 10 17 70 00 02 04
Register 1
value Hi
Register 1
value Lo
Register 2
value Hi
Register 2
value Lo
CRC
03 EA 04 6E F2 52
T [°C] aw
Response [Hex]:
Modbus
address
Function
code
Byte
count
Register 1
value Hi
Register 1
value Lo
Register 2
value Hi
Register 2
value Lo
CRC
46 10 17 70 00 02 -- 4A D0