1 2
 
1  Interface for LCD indicator and service port   
2 DIP switches 
Figure 32:  Communication board Modbus 
 
DIP switch  Function 
SW 1.1 
 
REPLACE MODE (transfer system data) 
On (1):  Enable: 
Replacement mode active 
Off (0):  Disable: 
Replacement mode deactivated 
SW 1.2 
 
REPLACE MODE (data transfer direction) 
On (1):  New sensor: 
When replacing sensor 
Off (0):  New electronic: 
When replacing secondary electronics 
SW 1.3 
 
PROTOCOL MODE 
On (1):  Enable: 
Selection of communication protocol via SW 1.4 
Off (0):  Disable: 
Selection of communication protocol via LCD 
display, DTM or Modbus  
SW 1.4 
 
PROTOCOL MODE 
On (1):  Configure/HART-RS485: 
Parameterization via DTM 
Off (0):  Operate/Modbus: 
Transfer of process data via Modbus 
communication to the master. 
 
 
 
The secondary electronics is located behind the front housing 
cover. The LCD indicator may have to be removed to provide 
access to the DIP switches. 
The DIP switches are used to make settings if an LCD display is 
not present. 
The interface for the LCD indicator is also used as the service 
port for device configuration. 
 
Replace mode (DIP switches 1 and 2) 
In normal mode the DIP switches 1 and 2 are in position 0. If a 
replacement procedure is necessary, they will be activated. 
•  When replacing the electronics or the sensor, disconnect the 
power supply and move DIP switch 1 to position 1. 
•  When replacing the secondary electronics, disconnect the 
power supply and move DIP switch 2 to position 0. 
•  The sensor can be replaced when DIP switch 2 is in position 1. 
 
Note 
We recommend resetting the corresponding DIP switch to 
position 0 after each replace operation. 
 
Protocol mode (DIP switches 3 and 4) 
By default, DIP switch 3 is in position 0. 
•  The communications protocol is then selected via the 
integrated LCD indicator, the DTM or Modbus 
communication. 
•  In position 1, the communications protocol is selected using 
DIP switch 4 only. 
 
DIP switch 4 is in position 0 by default and is active only if DIP 
switch 4 is in position 1. 
•  In position 0, the communications protocol is set to 
‘OPERATE/MODBUS’. This setting is intended for standard 
operation as a Modbus device. 
•  In position 1, ‘CONFIG/HART-RS485’, a DTM is needed for the 
parameterization of the device. Communication with a 
Modbus master is not possible in this setting.