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ADMA labotary bench test


The routine described below is intended to test the functionality of the inertial sensors of the gyro system, i.e. the accelerometers and gyroscopes. This function test is also a good way to become familiar with the ADMA and to gain experience in setting up the ADMA via Webinterface.

Setup and cabling#

The following components should be prepared for the function test:
• ADMA 3.0
• ADMA-Power supply cable
• ADMA-Ethernet cable
• Power Supply 9-32V DC
• Data Acquisition System (DAQ) with web browsers

Connect the cable and turn on the power supply. If both Power LEDs illuminate the ADMA is ready. These connections are pictured in the diagram below.

ADMA configuration for bench testing#

Configuring measurement data transmission via the CAN interface#

Go to menu 2️⃣ DATA LINK . Activate CAN data out for testing. This sets up the ADMA to transmit the data via the CAN port.

NOTE: COM and CAN mode can only be used exclusively!

The default CAN settings are:
• Base-ID: 100 dec
• Baudrate: 1000 kBaud

Selection of data packets to be transmitted#

The Data dialog is used to individually select the data packets which shall be transmitted by the ADMA. Data packets which are not required can be deactivated in order to reduce the transmission data volume.

The following general settings need to be selected for function test:
• Sampling rate "100 Hz"
• Output mode "v3.3.x"
• Coordinate system "Navigation"

The following data packets need to be selected:
• Rates (Body)
• Rates (Horizontal)
• Acceleration (Body)
• Acceleration (Horizontal)
• Tilt / Heading

Auxiliary systems#

This dialog is used to specify parameters which are related to auxiliary systems such as DGNSS settings and external velocity systems.

For the function test, it is necessary to deactivate all auxiliary systems as described below:
• External Velocity in X: "off"

Parameters#

The values of roll and pitch angle misalignment should be determinate via Auto Roll/Pitch alignment at menu 6️⃣ Parameters.

Save settings to ADMA#

The altered settings must be saved to the ADMA. This modified configuration can be saved on the hard disk for further tests. For this purpose, klick on Download.

Starting measurement#

Please specify a pre-alignment duration of 10 seconds.
To start a measurement, select Start measurement from the 7️⃣ LOAD/SAVE/START menu.
Start measurement will save settings as well.

When the ADMA measurement is running, the Measurement active value is 1.

Setup the Data Acquisition (DAQ)#

Configure your CAN device and load the GeneSys ADMA DBC Library v3.3.x in your Data Acquisition Software.

Pre-alignment in progress data channel Status_Alignment and Status_Count is indicated as shown below.

Status_AlignmentStatus_Count
110
19
18
1...

Once pre-alignment is completed (Status_Alignment = 0), the ADMA switches automatically to the measurement mode and starts to transmit current measurement data. The value of the data channel Status_Count will now count continuously from 0 to 255.

Important: The Kalman filter will need a couple of seconds to settle!

Static test#

Transient condition of the Kalman filter#

The Kalman filter of the ADMA can be activated without auxiliary systems like an external velocity or a (D)GNSS. It is possible to experience transient effects in the first few minutes (60-120 seconds). After this transient phase, stable values will be shown.
This transient phenomenon in the beginning of an initiated measurement is inherent with the design of the Kalman filter. It can only be compressed temporarily, though not eliminated.

Checking the system status#

Now check the data channels Status_Standstill and Error_Hardware. The value of Status_Standstill should be one, otherwise restart the measurement mode via Web interface.
If an error bit is set, the measurements are no longer valid. In this case, please contact our service department.

Status_StandstillError_Hardware
10

6.4.3 Checking the accelerations#

The ADMA should be positioned on a laboratory bench or similar facility, thus being placed on a close to horizontal surface. In addition, keep a flat support surface ready so that the ADMA remains level even when tilted. Tilt the ADMA in the axes as shown below, the following body-fixed accelerations should then be indicated:

ADMA ORIENTATIONAcc_Body_X (g)Acc_Body_Y (g)Acc_Body_Z (g)
00-1
001
-100
100
0-10
010

The measured acceleration of the observed axis should be between 1.01 g and 0.99 g. This test is helpful to ensure that the accelerometers have not been damaged.

Checking the rotational speed#

In a static state, the following rotational speeds should be indicated:

ADMA ORIENTAIONRate_Body_X (°/s)Rate_Body_Y (°/s)Rate_Body_Z (°)
0.0240.0260.038

The measured rotational speed of all axis should be between ±0,1°/s.
Without special software and hardware, it is not possible to test gyros accurately, so it is necessary to send the ADMA to GeneSys for calibration on a regular basis.

Dynamic Test#

As part of the dynamic test, the ADMA undergoes defined linear and rotary motion, i.e. along or about the systems sensor axis. The rotational speeds are checked first, beginning with the X-axis (roll), followed by the Y (pitch) and (yaw) axes, and then followed by the acceleration check in the same sequence of axes.

Checking the rotational speed#

The system should be rotated about the individual measurement axes in the sequence X, Y and Z.
The plotted data could look like this:

This data plot shows that ADMA detects negative as well as positive rotational speeds about all three measurement axes.

Checking the accelerations#

The system should be move linearly along the individual axes in the sequence X, Y and Z.
The plotted data could appear as follows:

This data plot shows that ADMA detects negative as well as positive accelerations along the three measurement axes.

Applikationsingenieur | bei GeneSys seit 2014

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