
APPENDIX 3 ________________________________________________________________________
VAISALA ________________________________________________________________________ 109
connection can be used. No address is needed when only one DMP248
transmitter is used; when several transmitters are connected to the
same line, each transmitter must be given an address in the initial
configuration.
A single transmitter can get its operating voltage from the master or it
can have its own (floating) power supply or it has the power supply
module in use.
The serial line structure is a parallel interfaced chain (daisy chain). At
the ends of the serial line there must be a DMP248 transmitter,
dynamic line adapter (120 ohm resistor in series with a 33 nF
capacitor) or line master. If a branch line is made with a junction box,
the branch should be shorter than 3 meters.
When connecting the device, follow the instructions given in the
figure in Chapter 1.
TX HI
TX LO
TWISTED PAIR WIRING
-
HOST COMPUTER
DUAL LOOP WIRING
TWISTED PAIR WIRING
HOST COMPUTER
RX LO
RX HI
TX H I
TX LO
RX LO
RX HI
TX HI
TX LO
RX LO
RX HI
TX HI
TX LO
RX LO
RX HI
TX HI
TX LO
RX LO
RX HI
120R
33 nF
TX HI
TX LO
RX LO
RX HI
120R
33 nF
120R
33 nF
NOTE: DYNAMIC LINE TERMINATION
REQUIRED IF NO DEVICE
AT THE END OF THE BUS.
NOTE: DYNAMIC LINE TERMINATION
REQUIRED IF NO DEVICE
AT THE END OF THE BUS.
DMP248
transmitters
1 to n pieces
DMP248
transmitters
1 to n pieces
SINGLE LOOP WIRING
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