Solar Pump Inverter Chapter 7 Communication protocol
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the slave shows corresponding function codes, digital address or sub-function codes as
the response. For objection responses, the slave returns a code which equals the
normal code, but the first byte is logic 1.
For example: when the master sends a message to the slave, requiring it to read a
group of address data of the inverter function codes, there will be following function
codes:
0 0 0 0 0 0 1 1 (hexadecimal 03H)
For normal responses, the slave responds the same function codes, while for objection
responses, it will return:
1 0 0 0 0 0 1 1 (hexadecimal 83H)
Besides the function codes modification for the objection fault, the slave will respond a
byte of abnormal code which defines the error reason.
When the master receives the response for the objection, in a typical processing, it will
send the message again or modify the corresponding order.
Error code and meaning
Modbus abnormal code
Code Name Meaning
01H Illegal command
The command from master cannot be executed. This
command is only for new version and this version cannot
realize. Slave is in fault state and cannot execute it.
02H Illegal data address
Some of the operation addresses are invalid or not
allowed to access. Especially the combination of the
register and the transmitting bytes are invalid.
03H Illegal value
When there are invalid data in the message framed
received by slave. Note: This error code does not indicate
the data value to write exceed the range, but indicate the
message frame is an illegal frame.
06H The slave is busy Inverter is busy (EPPROM is in storage)
10H Password error
The password written to the password check address is
not the same as the password set by P7.00.
11H Check error
In the frame message sent by the upper monitor, the
length of the digital frame is incorrect or the counting of
CRC check bit in RTU is different from the lower monitor.
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