Vaisala WMT52 User Manual
Page 50
User’s Guide ______________________________________________________________________
48 ___________________________________________________________________M210925EN-B
consumes 12 times less. And 1 Hz sampling rate makes it further
decrease to one fourth.
-
ASCII RS-232 Standby consumption with baud rates 4800 and
higher is typically 0.24 mA. With a low baud rate selection (1200
or 2400 Bd) this is reduced to less than 0.19 mA. The jumper wires
across TX+/RX+ and TX-/RX- add an extra 0.02 mA (they are
necessary only in 2-wire RS-485 mode).
-
ASCII RS-232 Polling mode and Automatic mode have equal
consumption. Thus Automatic mode is a little more economic,
since interpreting the poll takes more prosessing time than starting
the Automatic message. However, care should be taken when
selecting Precipitation Autosend mode, where the submodes M=R
and M=C may cause extra consumption in rainy conditions, as
triggered to send messages by the rain incidents.
-
ASCII RS-232 Data transmission adds 1 ... 2 mA to the standby
consumption during the message sending time. Also it should be
noted that the host device's input (data logger or PC) may
constantly draw some current from the TX line.
-
RS-485 and RS-422 Data interfaces consume about the same as
RS-232. But with long data cables the consumption during data
transmission may be much higher, especially when termination
resistors are used. On the other hand, the RS-485 driver is in high
impedance state when not transmitting - thus in idle state no current
can be drawn by the host input.
-
NMEA modes consume about the same as ASCII modes.
-
SDI-12 Native mode (M=S, C=1) has the lowest standby
consumption, about 0.1 mA. Note that it can also be used with RS-
232 terminals (PC or equivalent), see the SDI-12 connection
diagram in
. In this case the commands must
be in SDI-12 format, but no special line break signals are required.
The SDI-12 mode is for polling only.
-
SDI-12 Continuous mode (M=R) consumes about the same as the
ASCII RS-232 mode.
NOTE
If Heating function is enabled, SDI-12 Native mode consumes the
same as ASCII RS-232 mode.
When heating is on (or temperature is such it should be on), some
0.08 mA additional current is drawn from the operational power
supply.