Siemens SITRANS F M MAGFLO series - APPENDIX C - Modbus Communication Examples

Modbus RTU RS-485
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SFIDK.PS.023.D2.02
APPENDIX C
Modbus communication
examples
01 (0x01) Read coil status
Query
Slave address 1 byte
Function 1 byte
Starting Address Hi 1 byte
Starting Address Lo 1 byte
No. of Points Hi 1 byte
No. of Points Lo 1 byte
CRC 2 bytes
Slave address 1 byte
Function 1 byte
Byte Count 1 byte
Data Coil 1 byte
: :
Data Coil 1 byte
CRC 2 bytes
Response
03 (0x03) Read holding registers
Query
Slave address 1 byte
Function 1 byte
Starting Address Hi 1 byte
Starting Address Lo 1 byte
No. of Points Hi 1 byte
No. of Points Lo 1 byte
CRC 2 bytes
Slave address 1 byte
Function 1 byte
Byte Count 1 byte
Data Hi 1 byte
Data Lo 1 byte
: :
Data Hi 1 byte
Data Lo 1 byte
CRC 2 bytes
Response
Examples
Read absolute mass flow (4:03001)
Query: 1,3,11,184,0,2,70,10
Response: 1,3,4,64,195,82,139,98,200
Absolute mass flow = 6.10383 kg/sec.
Read absolute density (4:03005)
Query: 1,3,11,188,0,2,7,203
Response: 1,3,4,68,54,162,145,182,1
Absolute density = 730.54010 kg/m
3
Read sensor temperature (4:03007)
Query: 1,3,11,190,0,2,166,11
Response: 1,3,4,189,216,115,34,251,77
Sensor temperature = −0.10569 °C
Example:
Read Hold Totalizer 1 (0:00011)
Query: 1,1,0,10,0,1,221,200
Response: 1,1,1,0,81,136
APPENDIX C