Vaisala PTB200 - Manual (Page 10)

PTB 200 9 (28)
Digital Barometers
SSD/Operating Manual 24th February 1993 PTB200-O0284-1.1
2.7 Multiple transmitters on one RS 232C bus
It is possible to connect up to 99 PTB 200 barometers to one RS 232C
bus by using a connector box with diodes for each barometer
transmission line and one common barometer receiving line and ground
line (see Figure 6). Each barometer must be initialized to POLL mode
with a specific address (1...99) (see ADDR, SMODE POLL, OPEN and
CLOSE commands). The host computer must have sufficient buffering
to be able to handle several barometers.
G N D
G N D
T X
R X
R X
G N D
T X
R X
G N D
T X
B A R O M E T E R 1
B A R O M E T E R 1
B A R O M E T E R 3
R X
T X
H O S T
C O M P U T E R
Fig. 6 Connector box for several barometers on one RS 232C
bus