ML-x17 DATA LOGGER MANUAL
Manufacturers of low power instruments
page 66
powered till all enqueued messages are transferred. To minimize power consumption and latencies its
recommended to have a 360 degrees clear view to the sky with the smallest possible angle to the horizon
(the higher the antenna the better).
Note:
only parameters which are configured to output data to Satellite will be included in an enqueued
message.
4.20.4.2
Data transpond
You can choose to configure this driver to only send the last logged record (Actual Values) or all logged
records since the last successful data transmission (Log data).
Note
: log data will always be formatted in compacted binary format.
4.20.4.3
Message format
The messages can be enqueued in readable ASCII or in a compacted binary format. The compacted
binary format is about 20 to 80% more efficient saving a lot of communication costs, but needs specific
processing to be able to interpret the message.
See chapter “Compacted Data Format” for a description of this format.
The compacted format is limited to contain up to 15 logger parameters/channels. As textual parameter
codes would use to much data, the identification of the individual channels is based on a number between
1 and 15. Assigning the numbers to individual parameters is a matter of configuration by starting their
code names with a capital P followed by a number between 1 and 15. The P will be stripped of, as well as
any trailing characters, so you could specify meaning full codes like: P1TMP or P02HUM or P15LEV.
Note
: To make the most use of the compacted data: only enqueue parameters that are really necessary,
specify only significant digits for each parameter and specify
in “General”-settings a timestamp “round-
down” of one minute.
4.20.4.4
Backup mode
When the ‘Backup’ mode is selected satellite communication will be performed only if data transfer by
TCP, FTP, e-Mail or HTTP thru the cellular network is failing. You can also specify the number of cellular
transmission failures before satellite transfer takes place. When you set failures to 3 data transfer by
satellite will be performed every third cellular data transmission failure.
4.20.4.5
Swarm time update
The Swarm modem has an integrated GPS which can be used to synchronize the internal clock of the
data logger, its recommended to
switch time update to “On” unless you have a specific reason not to. The
GPS can also be used to record position, altitude, direction and speed.
4.20.4.6
RSSI
Swarm communication is very sensitive and can be jammed by background RF noise, the RSSI
parameter expresses the background noise in dBm and the lower the better. For successful
communication the RSSI should be lower than -88 dBm (e.g. -100 dBm is good).
•
Place antenna outdoors with clear view to the sky.
•
Place antenna >=1m above the ground or solid surfaces.
•
Keep antenna away from RF noise sources.
