Poll Mode; Rs 485 Network Settings - Vaisala HMP230 SERIES Operating Manual

HMP230 SERIES
Appendix 3: RS 485/422 serial port module

POLL mode

If a transmitter has been set to POLL mode, it will respond only to commands
sent with its address:
Addresses from 1 to 99 can be used. According to the RS 485/422 standard a
maximum of 32 devices can be connected on same bus, but the number can be
increased if the line length and/or baud rate is reduced.
More than one baud rate can be used on an RS 485 line. E.g. the host of the
line can use different baud rates with different devices (this makes it possible
to use the same address for several devices).
The line terminations must be dynamic; e.g. an RC circuit is used instead of a
simple resistor termination. Each RS 485 module has a dynamic line termina-
tion so it can be used at the end of a line.

RS 485 network settings

HMP230 settings
Full duplex/half duplex
Echo on/off
Terminal settings
Line feed after carriage re-
turn
HDX/FDX
When terminal is set to general <lf> (line feed) after <cr> (carriage return),
the listings will have two line feeds if also the HMP230 transmitters send line
feed.
112
send 22
RH= 24.4 %RH T= 29.1 'C
single pair
HDX
OFF
single pair
yes
FDX
U116en-2.2
dual pair
FDX
ON
dual pair
no
FDX