Omron MX2 - Message Configuration: Response; Transmission Time Required; Normal Response; Response When an Error Occurs

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Network Protocol Reference Section B-3
B-3-3 Message Configuration: Response
Transmission time required:
• A time period between reception of a query from the master and transmis-
sion of a response from the inverter is the sum of the silent interval
(3.5 characters long) + C078 (transmission latency time).
• The master must provide a time period of the silent interval (3.5 charac-
ters long or longer) before sending another query to an inverter after
receiving a response from the inverter.
Normal response:
• When receiving a query that contains a function code of Loopback (08h),
the inverter returns a response of the same content of the query.
• When receiving a query that contains a function code of Write in Register
or Coil (05h, 06h, 0Fh, or 10h), the inverter directly returns the query as a
response.
• When receiving a query that contains a function code of Read Register or
Coil (01h or 03h), the inverter returns, as a response, the read data
together with the same slave address and function code as those of the
query.
Response when an error occurs:
• When finding any error in a query (except for a transmission error), the
inverter returns an exception response without executing anything.
• You can check the error by the function code in the response. The function code of
the exception response is the sum of the function code of the query and 80h.
• The content of the error is known from the exception code.
Field Configuration
Slave address
Function code
Exception code
CRC-16
Exception Code Description
0 1 h The specified function is not supported.
0 2 h The specified function is not found.
0 3 h The format of the specified data is not acceptable.
2 1 h The data to be written in a holding register is outside the inverter.
2 2 h The specified functions are not available to the inverter.
• Function to change the content of a register that cannot be changed
while the inverter is in service
• Function to submit an ENTER command during running (UV)
• Function to write in a register during tripping (UV)
• Function to change the I/O terminal configuration which is not allowed.
• Function to change active state of RS (reset) terminal
• Function to write in a register during auto-tuning
• Function to write in a register locked by password
2 3 h • The register (or coil) to be written in is read-only