MX drives are totally different than Altivar drives. See modbus manual for MX eco drives in the attachment. Page 6 shows all important information and page 16 example with function code 17. If you want only to read parameters from MX eco, (not sending commands), then use function code 3 - read holding registers
The modus request will look: (each byte separated by "-")
Slave address - 16#03 - 16#00 - 16#FA - 16#00 - 16#02 - CRCLow - CRCHi
16#00FA is the address of the status word ZTW and 16#0002 means that 2 words will be read:
ZTW (status word) from address 16#00FA
Fact (actual frequency) from address 16#00FB
If you need to read more data, use another request.
Full request and response with function code 3 shown on page 32
The modus request will look: (each byte separated by "-")
Slave address - 16#03 - 16#00 - 16#FA - 16#00 - 16#02 - CRCLow - CRCHi
16#00FA is the address of the status word ZTW and 16#0002 means that 2 words will be read:
ZTW (status word) from address 16#00FA
Fact (actual frequency) from address 16#00FB
If you need to read more data, use another request.
Full request and response with function code 3 shown on page 32