Delta OHM HD45 17A, Manual

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Value Length Description
(continues…) 00h 1 byte Fixed value
(next item ID)
03h 1 byte Fixed value
(Number of fields)
00h 1 byte Fixed value
(first field ID)
Length 1 1 byte First field length
Value 1 (Length 1) bytes First field value (Manufacturer)
01h 1 byte Fixed value
(second field ID)
Length 2 1 byte Second field length
Value 2 (Length 2) bytes Second field value (Model)
02h 1 byte Fixed value
(Third field ID)
Length 3 1 byte Third field length
Value 3 (Length 3) byte Third field value (Firmware version)
Error responses
Commands correctly addressed and passing the CRC control can anyway generate
error conditions, for example, if you try to read a non-existent parameter or if you ask
the instrument to perform a function which is not compatible with the model.
In all cases where the instrument is not able to complete – for any reason – the
requested action, a response is generated containing an error code. The value entered
in the Function field corresponds to the received Function code with the most
significant bit (MSB) set to 1, in order to inform the “Master” unit about either the
error condition and the function that generated the error.
Response
Value Length Description
Function:
Requested function code
with MSB=1
1 byte
Error in requested function
execution
Data: 01h to 03h 1 byte Error type (Table 8.F)
The table below describes the error codes:
Tab. 8.F: Error codes
Error
code
Error
From
FW
Ver.
Notes
0001 Invalid function.
The instrument doesn’t manage the requested function.
1.00
0002 Invalid address.
At least one of the registers specified in the command does
not exist.
1.00
0003 Invalid data.
Data length doesn’t correspond to register length or value
out of acceptable range.
1.00
Further details relating to MODBUS protocol may be consulted at “www.modbus.org”.