Document No.: E20-018-00
13
6.6.
RS-422 Communication Line Wiring
For a boiler with a BL-model or XJ1-model controller mounted, a connection is required to the RS-422
communication conversion circuit board EC11 that is connected to the boiler-side CPU board. Use a
communication line wire (FCPEV
(*)
, 0.9 mm, 2P, copper braided screen) to
connect the RS-422
communication conversion circuit board EC11 of the EJ-210 to the RS-422 communication conversion
circuit board EC11 that is connected to the boiler-side CPU board.
Figure 6-3: Wiring of RS-422 communication line wires
NOTE 1: Connect the shield of the communication line wire to the FG terminal of the RS-422
communication conversion circuit board EC11 at the EJ-210 side.
NOTE 2: The RS-422 communication line requires no terminating resistance.
TXD(+)
TXD(-)
RXD(-)
RXD(+)
F G
TXD(+)
TXD(-)
RXD(-)
RXD(+)
F G
FCPEV, φ0.9 mm, 2P,
copper braided screen
Shield
<EJ-210 side>
RS-422 communication
conversion circuit board
<Boiler side>
RS-422 communication
conversion circuit board