EK280
Application Manual
113
c) Setting the device address
Each bus participant needs a unique identifier ("device address" or "bus address"), so that the bus master can
select a single data transmission subscriber. The device address set in the EK280 depends on which interface
protocol it uses:
Device address for LIS-200 protocol:
The device address for LIS-200 protocol can be any text up to 32 characters long (special characters not
allowed). With the above parameter file this has been set to the default value "1".
To change the EK280 device address, proceed as follows:
In the top of the device window open the path "
Parameter
" > "
Interfaces
" by clicking on the relevant
plus signs, and then select "
Terminal interface
".
In the "All parameters" window change the EK280 device address in the "Device address terminal
interface (bus address) "B.Adr”" line.
Device address for Modbus protocol:
The device address for Modbus protocol can be one digit between 1 and 247 inclusive. The default value is
"1".
To change the Modbus protocol device address, proceed as follows:
In the top of the enSuite device window open the path "
Parameters
" > "
Interfaces
" > "
Terminal
interface
" and then select "
Modbus
".
In the "All parameters" window change the EK280 device address in the "Modbus device address
(slave
address) "MBAdr”" line.
For further details on usage of Modbus protocol please see the document [6] (see page 5).
d) Setting time window for potential data retrievals
In the base configuration now displayed you can define time windows, during which data can be cyclically
retrieved from the EK280 via the RS485 bus. Time windows 5 and 6 are reserved for EK280 operation with a
direct terminal interface connection, and generally only time window 5 is used. Redundant time windows can
be deactivated by setting the time window start and end to the same value.
In the top of the device window open the path "
Parameters
" > "
Interfaces
" by clicking on the relevant
plus signs, and then select "
Call time windows
".
For call window 5, set the start to "00:00" and the end to "23:59" and then select the "Transfer
changes to device" icon at the top of the enSuite window.
Press the "
Transfer changes to device
" icon at the top of the enSuite window.
7.4.4
RS485 interface, without electrical isolation
If a connected RS485 interface device has a direct or capacitive ground potential connection, there is a risk of
interference coupling via ground loops, which may affect pressure or temperature measurements. Therefore
it is recommended that you use the isolated port as described in chapter 7.4.3 (page 111) if possible.
7.4.4.1 Wiring
i
When the EK280 is connected to a RS485 bus there must be no terminal resistors connected to
the bus!
Due to the current limit for intrinsically-safe apparatus approval, the EK280 cannot supply sufficient current to
power terminal resistors. At the data transfer rate used, terminal resistors are not required.