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
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Wireless Sensor Interface A720 (addIT™)
WARNING! Do not apply more than 10 Volts to the unit: permanent damage of the de-
vice may result. Note also, that the internal microcontroller will switch off the unit
when the battery voltage drops below 5.5 Volts, and under 5.9 Volts the RF opera-
tions may be stopped.
Figure 5. Connection of an external power supply.
3.4.3. Specifications
The A720 was intended to fulfill the specification of the ETSI 300 220, Class I, Sub-
classes a and b, but other national norms are similar to this (e.g. the CFR 47, Part 90,
Subpart J). Following are the main operational parameters of the A720:
Parameter Min Typ Max Unit
Common
Supply 5.0 6.2 10.0 V
Operating Temperature -30 +70 °C
Relative Humidity 10 99 %
Class Protection IP65
Data Rate (Using the On-board Software Modem) 1000
150
a
2000 bps
Operating Frequency (Low Band version)
b
432 450 MHz
Operating Frequency (High Band version)
b
450 470 MHz
Frequency Stability (-20 to + 60 °C) ±1.5 kHz
Frequency Stability (-30 to + 70 °C) ±2.5 kHz
Receiver
Sensitivity (10 db S/N) -93 dBm
Image Frequency Attenuation (1st IF = 45 MHz) 70 dB
POWER
I/O A
I/O B
+
-
Black
Red
5 to 10 Volt
RS232
+
+
Power Cable Serial Adapter Cable