LSI LASTEM M-Log – User’s manual
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5.2.1
Acquisition from sensors with serial or radio output
M-Log is able to acquire measures from sensors connected through serial port; both serial ports (if
they are present) are enabled for this function although it is preferable and advisable to use the
seirial port 2 for this application. M-Log actually supports LSI LASTEM CISS protocol (owner
communication protocol designed by LSI LASTEM and available in all sensors with
microprocessor; device for via radio reception by means of LSI LASTEM DEC301 outside
receiver).
The use of CISS protocol allows the connection to one or more LSI LASTEM sensors (even if they
have different model); every configured sensor must have an univocal network address as regards
other sensors connected on the same communication line. The connected sensors’ quantity
determines the sampling minimum slot of the instrument: consider usually 3 sensors per second (the
minimum acquisition time with 20 sensors must be set up 7 seconds at least). It is important that the
acquisition time programmed in the instrument through
3DOM
application (shown by the parameter
“
Update rate”)
must be the same of the spontaneous communication rate programmed by the sensor
through
LSM
program.
The sensor can be programmed to repeat the message communication several times, in order to
improve M-Log reception reliability; one repeat is usually enough (so the message has been
transferred twice); before the arrangement of several repeats, take into consideration: the power
autonomy of the sensor (if it is powered on through battery), and the further generated traffic. This
can make worse the reception reliability (depending on the connected sensors and the programmed
acquisition slots).
The acquisition of messages from the sensors happens as follow:
3DOM
application programs one
measure for each quantity that has been acquired and transferred inside the message by the sensor;
every measure is correlate to the respective sensor’s quantity by means of the sensor’s network
address, that specify: the origin sensor (in
3DOM
it’s the parameter
Probe ID
), and the ordinal
number of the quantity inside the message; for example in case of LSI LASTEM mod. DME811
sensor (programmed by network ID = 5) can be programmed up to 5 different measures, which
correspond to the quantity:
air temperature, relative humidity, surface temperature, temperature,
temperature.
The quantities number and their programming order aren’t binding (for example it’s
possible program
surface temperature, relative humidity)
, but the quantities sequence must have the
same order like in the message; in the previous example two M-Log measures must be programmed
as follow:
Quantity
Network
address
Measure
index
Surface temperature
5
3
Relative humidity
5
2
3DOM
application automates some configuration operations by means of its sensors library: for
example to program the LSI LASTEM mod. DME810 sensor press key
Add
from the measures list
window and then select the relevant code from the available sensors list: the application knows that
sensor is serial type and so it requires the sensor’s network ID; in succession the procedure
generates all needed measures for the sampling of the sensor in the right way.
