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3-11
Series 340 BN/MB Transmitter
+
-
Po
wer In
AC C /DC
AC L /DC
Output LED
Output
Pulse Out +
Pulse Out -
Pulse Input
NOTE:
maximum sinking current
is 100 mA @ 36 VDC
Device
(-) (+)
Figure 12: Sample Pulse Output Wiring Diagram
Connecting the RS-485 Buss
As shown in the Sample Wiring Diagram, the position of jumpers on each 340MB/BN transmitter and wiring between each
340MB transmitter and the RS-485 network are different depending on where the transmitter is installed, i.e. its nodal
position. For all but the final 340MB transmitter in a string, the three jumpers NT, PU, and PD should be in the open position,
and only the (+) and (-) network terminals should be connected to the RS-485 buss. For the final 340MB transmitter in a
Modbus network, the three jumpers NT, PU, and PD should be in the closed position, and all three network terminals (+), (-),
and REF should be connected to the Modbus buss.
NOTE:
The Model 340MB/BN transmitter default Modbus or BACnet polling address must be changed before it is
introduced into an existing network to avoid possible address conflicts. Please refer to programming instructions in the
previous section.
Figure 13: Sample Wiring Diagram to Modbus Network
Note 1: Biasing, circuitry, and resistors for PU, PD, and NT terminals are integral part of 340BN/MB transmitter.
Note 2: For the final 340MB transmitter in a given RS-485 network string, NT, PU, and PD jumpers should be in “Closed”
position. Otherwise, NT, PU, and PD should be in the “Open” position.
Note 3: For the final 340MB transmitter in an RS-485 string, all three network terminals (+), (-), and REF should be connected
to the buss. Otherwise, connect only terminals (+), (-) to the buss.