Table 2: Universal Access Registers
Modbus TCP/IP Register | Function |
9998 | ASD register number |
9999 | Read / write data |
To use this feature, first write the ASD register number that you wish to access to Modbus register 9998. Then, any subsequent read/write accesses to Modbus register 9999 will be redirected to the ASD register number defined in register 9998. In this manner, any ASD register can be accessed simply by changing the ASD register number held in Modbus register 9998, and then performing a read or write command on the read/write data register (9999).
For example, let’s say we would like to read a group of ASD configuration registers starting at register 100 from Modbus TCP/IP unit identifier 1
If the requested operation cannot be performed (typically due to such reasons as a
35