Thermo Fisher Scientific
Model 42
i
Trace Level Instruction Manual
C-1
Appendix C
MODBUS Protocol
This appendix provides a description of the MODBUS Protocol Interface
and is supported both over RS-232/485 (RTU protocol) as well as TCP/IP
over Ethernet.
The MODBUS Commands that are implemented are explained in detail in
this document. The MODBUS protocol support for the
i
Series enables the
user to perform the functions of reading the various concentrations and
other analog values or variables, read the status of the digital outputs of the
analyzer, and to trigger or simulate the activation of a digital input to the
instrument. This is achieved by using the supported MODBUS commands
listed below.
For details of the Model 42
i
Trace Level MODBUS Protocol specification,
see the following topics:
●
“
Serial Communication Parameters
” on page
C-1
●
“
TCP Communication Parameters
” on page
C-2
●
“
Application Data Unit Definition
” on page
C-2
●
“
Function Codes
” on page
C-3
●
“
MODBUS Parameters Supported
” on page
C-8
Additional information on the MODBUS protocol can be obtained at
http://www.modbus.org
. References are from MODBUS Application
Protocol Specification V1.1a MODBUS-IDA June 4, 2004.
The following are the communication parameters that are used to configure
the serial port of the
i
Series to support MODBUS RTU protocol.
Number of Data bits
: 8
Number of Stop bits
: 1
Parity
:
None
Data rate
: from 1200-115200 Baud (9600 is default)
Serial Communication
Parameters