15
The exception code is defined as follows:
01 Illegal function codes (received function codes are not supported);
02
Invalid data location (specified data location is beyond the scope of the meter);
03
Invalid data value (received data value sent to the host is beyond the data range of the corresponding address).
04 Equipment failure from the station (the data value received to the host is not currently allowed to be written)
5.4.2
Functional status of 01H/02H using Modbus
Upper computer required reading (01H/02H function of MODBUS)
ADD
Description
ADD
Data
CRC check
BYTE
BYTE
WORD
WORD
WORD
XX
XX(01H/02H)
XXXX
XXXX
XXXX( CRC check value)
Lower device reply(MODBUS function 01/02)
ADD
Function
Data length
Data
CRC check
BYTE
BYTE
BYTE
N BYTE
WORD
XX
XX(01H/02H)
XX
XXXX…….
XXXX( CRC check value)
Abnormal Lower device reply (MODBUS function of 81H/82H)
ADD
Corresponding
error function
Exception error code data
CRC check
BYTE
BYTE
BYTE
WORD
XX
XX(81H/82H)
XX (02H wrong address, 03H wrong
data)
XXXX( CRC check value)
5.4.3
Read using Modbus's functions of 03 or 04
Upper computer required reading (03H/04H function of MODBUS)
ADD
Function
Start address
Data
CRC check
BYTE
BYTE
WORD
WORD
WORD
XX
XX(03H/04H)
XXXX
XXXX(N)
XXXX( CRC check value)
Lower device reply (03H/04H function of MODBUS)
ADD
Function
Data length
Data
CRC check
BYTE
BYTE
BYTE
2*N BYTE
WORD
XX
XX(03H/04H)
XX(2*N)
XXXX…….
XXXX( CRC check value)
Abnormal Lower device reply(MODBUS 83H/84H function)
ADD
corresponding
error function
Exception error code data
CRC check
BYTE
BYTE
BYTE
WORD
XX
XX(83H/84H)
XX (02H wrong address, 03H wrong data)
XXXX( CRC check value)
5.4.4
Use the 05H function of Modbus to force the alarm state
Upper computer required reading (05H function of MODBUS)
ADD
Function
ADD
Data
CRC check
BYTE
BYTE
WORD
WORD
WORD
