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Interfaces to automation systems
8.2 Modbus interface
SITRANS SL
136
Operating Instructions, 12/2010, A5E01132948-04
8.2
Modbus interface
Note
You can obtain further information from the Modbus IDA user organization or on the Internet
at the Modbus internet site (
www.modbus.org
).
8.2.1
Modbus installation
Connection via RS485 interface
The SITRANS SL gas analyzer provides Modbus communication to a PC or an automation
system via an RS485 interface.
The SITRANS SL gas analyzer may be connected to a network. Such a network is normally
built as a bus topology which needs to be terminated via RC termination plugs. The same
applies to a point-to-point connection.
In a physical network up to 32 SITRANS SL analyzers may be connected to a Modbus
system via the RS485 interface.
Cable type
A two lined twisted pair cable with shielding is used for the Modbus connection. The
maximum cable length is limited to 1200 m.
Signal converter
If the PC has no RS485 interface, an RS232/RS485 signal converter must be linked between
the PC and the Modbus network.
Termination resistor
The termination resistor on the junction board must be switched off.
Connection
●
Data (N) = PROFIBUS A (electric connector 13 on junction board of SITRANS SL)
●
Data (P)= PROFIBUS B (electric connector 14 on junction board of SITRANS SL)
●
Shield= PROFIBUS shield (electric connector 15 on junction board of SITRANS SL)
Performance requirement
The minimum access interval from Modbus master is >100 ms.
Содержание SITRANS SL
Страница 106: ...Commissioning 6 4 Modbus configuration for SITRANS SL SITRANS SL 108 Operating Instructions 12 2010 A5E01132948 04 ...
Страница 206: ...List of abbreviations SITRANS SL 208 Operating Instructions 12 2010 A5E01132948 04 ...
Страница 212: ...Glossary SITRANS SL 214 Operating Instructions 12 2010 A5E01132948 04 ...