5-10
(4) Data protection
Writing via RS-485 is not restricted by function code F00 [Protect Data]. This code only protects
data in the case of keypad operation.
Writing via RS-485 is restricted by function code H29 [Protect Link Function] and the [WE-LK] X
function (Refer to section 5.1.5.2).
However, writing to H29 is enabled even in link edit disallowed mode.
5.1.6.2 Negative response and error response
If you attempt to perform the write operation when the communication data contains an error or the
inverter is not ready, the system will return a negative response and the write operation will not be
performed. You can check the error details with function code M26 or the keypad maintenance
screen. For details, refer to the section on type [34] communication error codes in Chapter 4, Section
4.2 "Function Code Tables."
Additionally, Modbus RTU protocol uses special codes (subcodes) for error responses. For details,
refer to the section on Modbus RTU.
5.1.6.3 No response
If the hardware on the inverter side detects a parity error or framing error, or the software detects a
sum-check error or CRC error because the communication data is physically damaged, the system
will return no response. You can check the reason for no response with function code M26 or the
keypad I/O check.
If the character interval of the data on the host side is greater than 20 ms due to a host hardware error,
the inverter will return no response. At this time, the communication data will be reset.
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