Eastron SDM630-Modbus MID V2 - Error Handling and Diagnostics

Function
10
Starting Address High
00
Starting Address Low
02
Number of Registers High
00
Number of Registers Low
02
Error Check Low
E0
Error Check High
08
3.10 Exception Response
If the slave in the “Write Holding Register” example above, did not support that function then it
would have replied with an Exception Response as shown below. The exception function code
is the original function code from the query with the MSB set i.e. it has had 80 hex logically
ORed with it. The exception code indicates the reason for the exception. The slave will not
respond at all if there is an error with the parity or CRC of the query. However, if the slave can
not process the query then it will respond with an exception. In this case a code 01, the
requested function is not support by this slave.
Field Name
Example (Hex)
Slave Address
01
Function
10 OR 80 = 90
Exception Code
01
Error Check Low
8D
Error Check High
C0
3.11 Exception Codes
3.11.1 Table of Exception Codes
Eastron Digital meters support the following function codes:
Exception
Code
MODBUS
Protocol name
Description
01
Illegal Function
The function code is not supported by the
product
02
Illegal Data Address
Attempt to access an invalid address or an
attempt to read or write part of a floating point
value
03
Illegal Data Value
Attempt to set a floating point variable to an
invalid value
05
Slave Device Failure
An error occurred when the instrument
attempted to store an update to it’s
configuration
3.12 Diagnostics
MODBUS Protocol code 08 provides a number of diagnostic sub-functions. Only the “Return
Query Data” sub-function (sub-function 0) is supported on Eastron Digital meters.
Example
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