Acceleration sensor module

Description

The "accelerometer" module produces the acceleration values from the LIS3DH 3-axis acceleration sensor acceleration sensor, which is located on the smartRAIL systems. In addition, the module calculates three further series from the measured values produced, consisting of the local maximum, local minimum and the quadratic mean and produces these aggregation aggregation values in additional channels for each axis.

The standard designation of the axes corresponds to the axis designations specified by the system (can be derived either from the imprint on the housing or from the data sheet).

The measuring frequency and measuring range of the sensor can be adjusted via the JSON configuration of the module. See Sensor configuration JSON

The names of the axes can be manually overwritten by the "channelnames" field of the JSON configuration to adjust the names of the axes after installation, depending on the alignment of the system. after assembly. The "channelprefix" field allows you to overwrite the default prefix ( corresponds to the module name specified in the config) with a user-defined prefix.

Interfaces & protocols used

• I2C

JSON configuration

Minimum configuration

{
  "module": "accelerometer",
  "factory": "accelerometer",
  "config": {
  }
}

Explanation of the minimum configuration

Preset values (can be derived from the parameter description table):

• 10Hz Signal rate
• 2g Measuring range
• 1000ms RMS interval

Produces the raw values of all three axes, as well as the local extremes and an RMS transformation according to the following scheme, for all three axes.

Example for the X-axis:

• "accelerometer.x"
• "accelerometer.x.rms"
• "accelerometer.x.max"
• "accelerometer.x.min"

Maximum configuration

{
  "module": "accelerometer",
  "factory": "accelerometer",
  "config": {
    "sensor": {
      "rate": 400,
      "range": "4g"
    },
    "channelnames": {
      "xaxis": "acceleration.y",
      "yaxis": "acceleration.z",
      "zaxis": "acceleration.x"
    },
    "rmsInterval": 100,
    "extremeInterval": 10000
  }
}

Parameter description

Parameter name	Required	Data type	Valid value range	Default	Description
channelPrefix	No	String	Any	Name of the module	Prefix to be added to all channels of this module *
rmsInterval	No	Integer	[50,100,500,1000]	1000	Interval length of the root mean square [ms] **
extremeInterval	No	Integer	[100,1000,10000,60000]	1000	Interval length of the aggregation to the maximum and minimum
sensor	No	JSON Object	-	see below	Fields for sensor configuration
channelnames	No	JSON Object	-	see below	Overwrite channel names

* If both the channelprefix and channelnames fields are specified in a config, the value in the channelprefix value in channelprefix` is ignored for any axis for which a specific channel name has been specified.

** To guarantee that a meaningful quadratic mean is calculated, the module resets itself to the module resets itself to the 1000ms value if the combination of signal rate and RMS interval length would result in would result in less than 2 measured values being used for the calculation.

i.e.:
sensor.rate = 10hz
rmsInterval = 100ms

Sensor configuration structure

Parameter name	Required	Data type	Valid value range	Default	Description
rate	No	Integer	[1,10,100,200,400]	10	Signal frequency of the three axes [Hz]
range	No	String	["2g", "4g", "8g"]	"2g"	Measuring range of the three axes

Overwrite the channel names

Parameter Name	Required	Data Type	Valid Value Range	Default	Description
xaxis	No	String	Any	"accelerometer.x"
yaxis	No	String	Any	"accelerometer.y"
zaxis	No	String	Any	"accelerometer.z"

The channel names of the transformations are created from the above-mentioned parameters and the suffixes ".rms", ".rms" and ".rms". suffixes ".rms", " .min", ".max" respectively.

i.e.
For "channelnames.xaxis = acc.z" =>
acc.z // Raw values
acc.z.min
acc.z.max
acc.z.rms

Module Information

Information	Value
Author	optiMEAS Measurement and Automation Systems GmbH
since smartCORE	-
Module Type	Producer
Dependencies