MKal Use Mechanical Field Calibration

1
MKal Use - Mechanical Field Calibration

• First, please control the Articulograph AG100.
  You may use the ART-just program or ART.exe or
  ART8.exe
• The system has to be warmed up
• The sensors in the calibration magazine at the
  calibration stand show your right ADC-values
  (Usually about 500 in the center).
• The offsets are all higher than zero
• The sampling rate should be at 500 Hz
• The sensors in the magazine should be fixed with
  a tape, however as thin as possible

2
MKal measurement

• Put the helmet on the MKal unit, make sure that
  the green transmitter coil is at the side, which
  is marked as forhead, the blue at the side marked
  as chin

3
Position of the helmet

• Lead the sensor cable through the hole at the
  side, to avoid, that the signals of the
  transmitter coils will interfere

4
Position the calibration magazine

• Put the magazine in the center position to start.
• Sensor 3 has to be in the center. If you see at
  the right as well as at the left side of the
  holder one raster mark, the sensor 3 will be in
  the center.

5
Fix the magazine at the right position

• slip the magazine through the hole and make sure
  that it clicks into the right position

6
Start Mkal Program

• Now, please start MKal64.exe. The program should
  be at your actual folder for ART-just and all the
  other Art programs
• step 1 -
• load the actual ART715.cfg file
• step 2 -
• measure positions
• choose channel 1-5
• choose the distance of 0 mm
• confirm with ok

7
Measuring clockwise - 1

• Now you see a clock at the monitor which shows
  24 positions
• Start with position 0
• Tip a few times with your finger against the cone
  to click into the right position
• Make sure that the monitor shows the same
  position as the MKal
• Put the hands away from the system and click
  measure

8
Measuring clockwise - 2

• Please pay attention, you see the clock at the
  MKal in the other direction. However the numbers
  has to be the same.
• Repeat this with all 24 position (0 - 0.30 - 1 -
  1.30 - etc) for highest precision or if you want
  to do it faster, for 12 positions (0 - 1 - 2 -
  etc)
• Stop with finish and cancel
• Repeat the procedure with distance 40 mm
• Close with finish and cancel
• Dont measure the distance 80 mm. It is at the
  border of the measuring area. The results usually
  will be not as good, as measuring only distance 0
  and distance 40

9
calculation of the powers

• after clicking step 3 and step 4 you will get the
  new powers for your system. They should be
  between 2.8 and 3.1

10
calibration of the sensors

• Put the helmet back on the calibration stand and
  tilt and rotate the sensor to get the maximum
  signal, like a usually daily calibratation
• start with sensor1
• push into the center
• click retry to reset the value
• find maximum
• click take
• repeat for the other sensors
• step 6
• calibrate radius table
• Now you have to store the result as Ratab.art
  into the actual folder

11
Continue

• Now you are ready to do your measurement with
  ART.
• If you continue with ART-just preparation for
  study please call the page sensor calibration,
  however dont do any calibration. It is only that
  the system knows, that the sensors are well
  calibrated
• You can do the accuracy test with ART-just to
  look for your results. The deviation should be
  less than 2 .
• If you want to use the 15 powers to calibrate the
  next time only with ART-just, please put in the
  powers into the list of powers of the ART-just
  program.