Ametek AMEVision 3050-TE, User Manual

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A-4 | 3050-TE Moisture Analyzer
MODBUS FUNCTIONS
As the Modbus protocol is designed for communication among Program-
mable Logic Controllers (PLCs), not all Modbus function codes supported
by a slave PLC are applicable to the Model 3050 analyzer. Only the follow-
ing relevant function codes are implemented:
In accordance with MODBUS protocol specifications, all address referenc-
es in Modbus messages are numbered relative to zero. For example, the
first holding register in a Modbus slave being referenced as 40001 would
be addressed as 0.
EXCEPTION CODE
The Model 3050 analyzer Modbus protocol implementation supports
these exception codes:
Unsupported function requests from the Modbus master result in excep-
tion code 01 being returned. Illegal address exception code is returned
when the requested address is outside the allowed range or writing to a
read-only location. When the values to be written to holding registers are
outside the appropriate ranges, exception code 03 is returned.
CODE DESCRIPTION
03 Read m ultiple holding registers (4x references)
06 W rite one holding register (4x references)
16 W rite m ultiple holding registers (4x references)
17 Read slave ID and status inform ation
CO DE DESCRIPTIO N
01 Illegal Function
02 Illegal Address
03 Illegal Value