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Vaisala HMP228 User Manual

Page 102

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HMP228
Appendix 5: Digital current loop module

M210282en-A

96

POLL mode

If a transmitter has been set to POLL mode, it will respond only to commands
which include its address:

send 22
aw= 0.244 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.

Current loop settings

HMP228 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 when also the HMP228 transmitters send
line feed.