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Operation
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32
5.3.3
Confirming error messages
For the sake of plant and process safety, the measuring device can be configured in such a way that
fault messages displayed ($) always have to be rectified and acknowledged locally by pressing F.
Only then do the error messages disappear from the display.
This option can be switched on or off by means of the "ACKNOWLEDGE FAULT MESSAGES"
function (È "Description of Device Parameters" manual).
Note!
• Fault messages ($) can also be reset and confirmed via the status input.
• Notice messages (!) do not require acknowledgment. Note, however, that they remain visible
until the cause of the error has been rectified.
5.4
MODBUS RS485 communication
5.4.1
MODBUS RS485 technology
The MODBUS is an open, standardized fieldbus system which is deployed in the areas of
manufacturing automation, process automation and building automation.
System architecture
The MODBUS RS485 is used to specify the functional characteristics of a serial fieldbus system with
which distributed, digital automation systems are networked together.
The MODBUS RS485 distinguishes between master and slave devices.
• Master devices
Master devices determine the data traffic on the fieldbus system. They can send data without an
external request.
• Slave devices
Slave devices, like this measuring device, are peripheral devices. They do not have their own
access rights to the data traffic of the fieldbus system and only send their data due to an external
request from a master.
2
Fig. 20:
MODBUS RS485 system architecture
1
MODBUS master (PLC etc.)
2
MODBUS RS485
3
MODBUS slave (measuring devices etc.)
3
3
3
Cubemass DCI MODBUS RS485
1
3
Endress+Hauser
A0004398
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