Vaisala HMP230 - Manual (Page 131)

HMP230 SERIES
M210225en-B Appendix 4: Digital current loop module
125
POLL mode
If a transmitter has been set to POLL mode, it will respond only to commands
sent with its address:
send 22
RH= 24.4 %RH T= 29.1 'C
Addresses from 1 to 99 can be used. According to the 20 mA current loop
standard current flows with no transmission on line. A maximum of 6 devices
can be connected on same single loop line, but the number can be increased to
9 by using dual loop wiring.
More than one baud rate can be used on a current loop line. E.g. the host of
the line can use different baud rates with different devices (this makes it pos-
sible to use the same address for several devices).
Current loop settings
HMP230 settings single pair dual pair
Full duplex/half duplex HDX FDX
Echo on/off OFF ON
Terminal settings single pair dual pair
Line feed after carriage return yes no
HDX/FDX FDX FDX
When terminal is set to general (line feed) after (carriage return),
the listings will have two line feeds if also the HMP230 transmitters send line
feed.