Technical Manual

40
Wireless Sensor Interface A720 (addIT™)
to build the average that will be stored. The default storage is 900 (15 minutes)
and samples is 3 (3 samples per quarter of an hour). Example:
— if you want to sample the inputs (sensors) every minute and build an hour-
ly average, issue the command SET SLOT 3600 60.
— if you want to sample the inputs once per hour and store the values as they
are, then the command SET SLOT 3600 1 will do the job.
In order to better understand the importance the samples parameter has, a table is
provided showing addIT’s expected operation time on a fully charged battery and a
50 mA total consumption for the sensors:
Note: Radio activity refers to the fact that one base station and between one and three A730MD sta-
tions/addITs are active on the same operating frequency as the addIT under test.
• SET BL ll ul – sets band limits; ll is the minimum allowable frequency, while ul
is the maximum allowable frequency. This command effectively limits the us-
er’s possibility to change the device’s operating frequency and it can be used
to fulfill specific requirements existing in certain countries. Example:
— if the law in a country limits the operation of the device between 433.150
and 434.750 MHz, then the command is
SET BL 433150000 434750000.
— if the users are not allowed to change the frequency at all, then use the same
frequency for both ll and ul: SET BL 433925000 433925000.
Note: The SET BL command is not documented in the user manual.
• SET FREQ freq step – sets the unit’s operating frequency; freq is the frequency
and step is the channel spacing (both expressed in Herz). Example:
— suppose you want to change the frequency of an addIT to 467.1125 MHz
with a channel spacing of 12.5 kHz. After converting all the values to Hz, the
command to be used is SET FREQ 467112500 12500.
Note: The SET FREQ command may return an error if trying to program a frequency outside the
band limits; see SET BL command.
• SET RSSI value – set the Relative Signal Strength Indicator threshold. The facto-
ry default is set to 58 units. The RSSI threshold is used to detect if there is any
radio activity on the channel. The value set must be approximately 30% higher
than the actual measured value when no signal is present on the channel. To
measure the actual value use the command RSSI (explained later in this chap-
ter). Example:
— to set the RSSI threshold to 55, use the command SET RSSI 55.
Radio activity
Sensor sampling
(samples/15 min)
Average
consumption (µA)
Estimated
operation (days)
No No sensors 450 92
Yes No sensors 540 77
Yes 1 750 55
Yes 3 (default) 1080 38
Yes 5 1450 28
Yes 15 3100 13