Technical Manual
Table Of Contents
- Wireless Sensor Interface A720 (addIT™)
- 1. About the A720
- 2. Hardware
- 4. Software
- 4.1. AMOS
- 4.2. Mode Check
- 4.3. A/D Task
- 4.4. The Terminal Task
- 4.5. The Radio Interface Task
- 4.5.1. Digital Squelch
- 4.5.2. Modulation Technique Used
- 4.5.3. Generic Format of a Radio Frame
- 4.5.4. Data Frames
- 4.5.5. Frame Types
- 4.5.5.1. Request
- 4.5.5.2. Broadcast Answer
- 4.5.5.3. Set I/O Request
- 4.5.5.4. Read I/O Answer
- 4.5.5.5. Broadcast Request
- 4.5.5.6. Ping
- 4.5.5.7. Pong
- 4.5.5.8. Memory Dump Request
- 4.5.5.9. Memory Dump Answer
- 4.5.5.10. Data
- 4.5.5.11. Set ID
- 4.5.5.12. Set Slot Time and Sample Rate
- 4.5.5.13. Set Frequency
- 4.5.5.14. Set Battery Charge Levels
- 4.5.5.15. Set Pulse Counters Parameters
- 4.5.5.16. General Acknowledge
39
The Terminal Task
The A/D task is not executed at each 0.5 seconds interval, but rather every 5 minutes
(default). This parameter can be user configured (it is stored in the EEPROM section).
After the sensors inputs are sampled their values are averaged and stored as a slot in
the EEPROM FIFO buffer, time stamped. The number of samples is by default 3, but
is user configurable (this parameter is stored in the EEPROM section). These param-
eters are defined and can be changed by the SET SLOT command (see also “Supported
Commands” on page 39).
A special method of averaging is used in order to deal with various sorts of sampled
values (e.g. wind direction). In addition, the pulse counters are stored in the EE-
PROM with the slot and cleared afterwards.
4.4. The Terminal Task
The terminal offers a minimum of commands needed to configure and administer
the device, like setting and reading parameters (time, frequency, sampling rate, etc.),
checking the radio subsystem (switch it in various modes – receive, transmit, etc.).
The device enters in terminal mode whenever the mode checking routine senses that
a serial cable is inserted in the
POWER connector. Periodically, it checks for that con-
dition, in order to automatically exit this mode (see also “Mode Check” on page 36).
In the inset are depicted the connection pins on the POWER connector, where the se-
rial cable is plugged.
Note: The interface is TTL, not RS-232! An adapter cable provided by Adcon must be used.
4.4.1. Supported Commands
Following is a list of available commands and an explanation of their use (the com-
mands are listed in upper case, but you can use lower case too, the device is not case
sensitive).
4.4.1.1. The SET Series of Commands
• SET OWNID nnnn – where nnnn is the Id number of the unit. The Id number
must be identical to the one written on the unit’s label.
• SET PMP bl bh – set the power management parameters. bl is the lower battery
level (the threshold where the charging of the battery will be switched on) and
bh is the higher battery level (the charging will be switched off). Both bl and bh
are expressed in volts x 10 (e.g. 72 means actually 7.2 V). Default values (fac-
tory programmed) are 65 and 72, meaning 6.5 and 7.2 volts respectively. Ex-
ample:
— if you want to change the switch on threshold to 6.3 and the switch off
threshold to 7.0 volts, issue the command SET PMP 63 70.
• SET SLOT storage samples – configures the input sampling and storing inter-
vals: storage represents the time (in seconds) elapsed between two slots stored
in the internal memory, while samples represents the numbers of samples used