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Q5: How to read the status of each connection?
A5: The status for each connection is saved in the sequence of polling definition from local register
address 39600. The maximum number of polling definition in the config.csv file is 250, so the
available address for the connection status is from 39600 to 39849. A Modbus master use
function code 04 to read the status, up to 126 register of status can be read in one command.
For example, the status of the graph shown above is presented as the third column in the
following table.
The value of status:
0
: Good
0xFFFF
: Timeout
0x8
X
YY
: Exception Rresponse.
X
- Modbus Function Code.
YY
- Exception Code.
Exception
Code
Name
Meaning
01
Illegal Function
The function code received is not an allowable action.
02
Illegal Data Address
The data address received in the query is not an
allowable address.
03
Illegal Data Value
A value contained in the query data field is not an
allowable value.
04
Illegal response
length
The request would generate a response with size bigger
than that available for MODBUS protocol.
Def.
number
Address
Status
Status display on web page
Def.#001
39600
0
GOOD
Def.#002
39601
0
GOOD
Def.#003
39602
0xFFFF
TIMEOUT
Def.#004
39603
0x8201
ERROR: ILLEGAL FUNCTION
Def.#005
39604
0
GOOD
Def.#006
39605
0x8402
ERROR: ILLEGAL DATA ADDRESS
