MTD2000 AT Command Guide R12
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19 Analog IO Command
19.1 Analog Input Port – AT$AI
This command allows user to set analog input thresholds for monitoring, which is in
term of digital value. When the analog input level is equal or higher than the preset
threshold, the analog input status flag in the event table will be set.
The ADC reference voltage is 3.3 volts. The external power level is reduced by ten
times before connecting to the ADC channel.
For the conversion from digital value to actual voltage, refer to “ADC Conversion
Formula” below. The factor value for external power level is 31. For example, the
voltage of 12 V is corresponding to digital value of 372.
ADC Conversion Formula
Analog Input Level = (Digital Value / Factor) volts
Syntax
Command
Response
AT$AI=<Mode>[,<Threshold>]
Note: Write setting.
OK
AT$AI?
Note: Query setting and current analog input
level.
$AI: <Mode>,<Threshold>,<Current>
Parameters
Mode
0 – Disable
1 – Enable
Default is 0 (Disable)
Threshold
Analog input threshold in digital value (0 to 1023 units)
Default is 0 units
Current
Current analog input level in digital value (0 to 1023 units)
Example