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Appendix C
Modbus Register Map
The following sections outline each of the sections of registers as defined by the Modbus protocol.
These groups are as follows:
•
Coils
–
Single bit registers that can be written to cause an action
•
Input Discretes
–
single bit registers that are a read only status
•
Input Registers
–
16 bit registers that are a read only status
•
Holding Registers
–
16 bit registers that can be read and written.
Note: Any registers that are grayed out have not been implemented. Writes to these registers will be
ignored. Reads from these registers will return unpredictable results.
Note: Modbus uses a register number, which starts at 1 to describe the location of data. The actual
address that is passed in the protocol layer is 0. This means that depending on the tool you are using,
you may need to subtract 1 from the register number to access the appropriate data.
Coils
Table 9 - Available Coils
Register
Description
Read
Write
Basic Control
0:0001
Restart Sensor
N/A
1 - Restart
0:0002
Reset Velocity Log
N/A
1 - Reset Log
0:0003
Reset Error Log
N/A
1 - Reset Log
0:0004
Time Format
Current Value
0
–
Seconds
1
–
H:M:S
0:0005
Units
Current Value
0
–
Imperial
1 - Metric
0:0006
Restart Modbus Interface
N/A
1 - Restart
0:0007
Reset Daily Statistics Log
N/A
1
–
Reset Log
0:0008
Reset Total Statistics Log
N/A
1
–
Reset Log
0:0009
Reset Modbus peripheral Error Log
N/A
1
–
Reset Log
0:0010
Reset Arrival Log
N/A
1
–
Reset Log
