AC Command — Integrated Accelerometer

Real-time G-force value queries.

What is it used for?

Use case	Description
📊 Driving monitoring	Detect accelerations, braking and sharp turns
🚗 Movement detection	Identify when the vehicle is in motion
⚠️ Impact alerts	Trigger alerts when G thresholds are exceeded
📐 Inclination	Verify device position and orientation

Description

Allows querying G-force (acceleration) values measured by the integrated accelerometer in the hardware. Resulting or absolute magnitudes of up to 8G can be measured in three axes (X, Y, Z).

Features

3-axis measurement (X, Y, Z)
Range: 8G
Resolution: Hundredths of G
Configurable triggers via CXAC

The AC trigger is NOT recommended for conditional use in event engine rules. Use AC+ edges only in triggers (TRG).

Commands

Query accelerometer

QAC

Response:


RAC Xsaaa Ysbbb Zsccc

Parameters:

s: Sign (+ or -), positive reference = gravity acceleration
aaa: X-axis magnitude in hundredths of G (000-800)
bbb: Y-axis magnitude in hundredths of G (000-800)
ccc: Z-axis magnitude in hundredths of G (000-800)

Examples

Query at rest


>QAC<
>RAC X+000 Y+018 Z+100;ID=1234;+18<

Interpretation:

Z+100: 1.00G (gravity acceleration, vehicle at horizontal rest)
Y+018: 0.18G (small lateral inclination)
X+000: 0.00G (no longitudinal acceleration)

Rule with acceleration trigger


>SRL10E;TRG=AC+;ACC={GGPXXL}<

Generates GP report each time the acceleration threshold configured via CXAC is exceeded.

Threshold Configuration

Acceleration thresholds are configured via the CXAC Command.

The AC trigger remains active for 1 second after exceeding the configured threshold.

AC Signals

Available edges

Signal	Activation
`AC+`	Exceeded acceleration threshold (configured in CXAC)

Restrictions

Only positive edge (+) available
NOT suitable for use in conditionals (CND)
Only use in triggers (TRG)
Duration: 1 effective second

Value Interpretation

Axis reference

According to standard installation orientation:

X-axis: Longitudinal (vehicle forward/backward)
Y-axis: Lateral (left/right)
Z-axis: Vertical (up/down)

Typical values

Situation	X	Y	Z
Horizontal rest	0.05G	0.05G	+1.00G
0.5G acceleration	+0.50G	0.05G	+1.00G
0.5G braking	-0.50G	0.05G	+1.00G
Right turn	0.05G	-0.30G	+1.00G
Left turn	0.05G	+0.30G	+1.00G

Response Breakdown

QAC Example


>QAC<
>RAC X+000 Y+018 Z+100;ID=1234;+18<

Field	Value	Interpretation
`RAC`	-	Accelerometer Response
`X+000`	+0.00G	X-axis: no acceleration
`Y+018`	+0.18G	Y-axis: 18% inclination
`Z+100`	+1.00G	Z-axis: normal gravity
`ID=1234`	1234	Identifier
`+18`	18	Checksum

Limitations

Don’t use AC in CND: Only in triggers (TRG)
Short duration: Signal active for 1 second
Calibration: Requires correct device installation
Sensitivity: Configure thresholds according to application

Compatibility

💾Firmware v1.08.00

SPLegacy

ULLegacy

MTLegacy

💾Firmware v1.00.00

SP-IOT

SM-IOT