Lab Chromameter (CR-410) SOP

Submitted by dylan on Wed, 2007-10-03 22:24.

Notes

  1. There is an excellent manual, stored behind the blue foam in the lid of the case.
  2. If you need to keep track of date/time, be sure to install batteries in the sensor head, and then set the time-- you will need to use the software to do this.
  3. When working with dusty material it is a good idea to do regular checks, as the light source will get progressively obscured. Consider using the granular materials attachment.
  4. Use an indirect blast of compressed air to clean the color sensor / illuminant window after every sample.

Calibration of the CR-410

  1. power on the unit, and press the 'Cal' button
  2. place the unit on the white standard calibration tile
  3. verify the values on screen match the "C" light standard values listed on the calibration tile case
  4. press the measurement trigger button
  5. the unit will take three samples, and will enter measurement mode

Downloading data from the sensor head

  1. with the sensor head turned off, plug in serial cable
  2. power on the unit, then immediately press the 'enter' key
  3. optionally adjust the 'baudrate' to 19200
  4. move the cursor to 'PC Mode', and press the 'enter' key
  5. open the ut400.exe application
  6. optionally adjust connection settings, then click on the connect button.
  7. Set an output target (use a text file).
  8. Click on the 'Intrument...' button, and then choose the 'Upload' option.
  9. Upload the data (instrument to computer)
  10. click on 'Save As' in the text output window, and save the results to a file.
  11. The data should be saved in XYZ colorspace
  12. you can optionally delete the data from the sensor head, using the ut400.exe application

Downloading data from the data processing unit.

  1. Transfer data from sensor head to data processing unit (this erases the data from the sensor head). This is done by connecting the two units and then importing data from the sensor head
    1. press 'Option'
    2. select 'Import'
    3. select 'NEW'
    4. press 'Enter'
  2. Attach data processing unit (DPU) to serial port and open ut400.exe
  3. Set the DPU to 'remote mode' by first pressing the 'index set' button and scrolling down to this setting.
  4. Connect cable to DPU, and click on the connect button.
  5. Set an output target (use a text file for maximum compatibility).
  6. Click on the 'Intrument...' button, and then choose the 'Upload' option.
  7. Upload the data, note that if there are several sets of data on the device (pages) you must select the appropriate page first.
  8. click on 'Save As' in the text output window, and save the results to a file.
  9. The data should be saved in XYZ colorspace

Notes for non-Windows Users

If you are using wine, you will need to:

  1. configure the serial port (http://www.winehq.com/site/docs/wineusr-guide/misc-things-to-configure#AEN408)
  2. copy msvcirt.dll from a working windows install in the windows/system32/ folder in your wine home directory
  3. Start the program with wine:
    wine ~/.wine/drive_c/Program\ Files/Minolta/CR-400\ Utility/ut400.exe

Chromameter Soil Colors in XYZChromameter Soil Colors in XYZ (see below)

 
Processing in R:

# example processing:
# note that the row name corresponds to the sample_id

require(colorspace)
x <- read.csv('data_dump_4-7-2007.csv', header=FALSE)
c <- data.frame(id=x$V1, X=x$V2, Y=x$V3, Z=x$V4)

# cast to XYZ object
c.xyz <- XYZ(c$X, c$Y, c$Z)

# plot colors in XYZ colorspace
plot( c.xyz, cex=1.5)

 
Other examples of processing color data in R

 
Related Literature

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