Digital Communications - ero electronic ELK Manuel Utilisateur

2.12. Digital Communications

Optional
Digital communications uses the Modbus protocol.
The interface may be ordered as RS232 or RS485 (2-
wire).
•
Isolated output 240Vac CATII
RS232 Connections
Rx Tx Com
Local Ground
Screen
ELK
16
Common
17
Rx A(+)
Tx B(-)
18
Part number HA028438. Issue 3.0.
RS485 Connections
Rx Tx
RxB/
RxB/
TxB
TxB
ETK
4
Common
5
Rx A(+)
220Ω termination
Tx B(-)
6
Oct-05
Com
Screen
Tx Rx Com
*
RxA/
Com
TxA
Twisted pairs
resistor
* RS232/RS485 2-wire
communications converter
eg Type KD485
220Ω termination
resistor on last
controller in the line
Daisy Chain to
further
controllers
ELK ETK
16 4
Com
Rx A(+)
17 5
Tx B(-)
18 6
21