Collecting Readings

Last update - 8/5/2009

Readings are best made in clear sky or lightly cloudy (cirrus type) conditions. Useful readings can be obtained in irradiance levels down to about 300 watts per square meter or just before shadows disappear.

If the radiometer has any bands 1100 nm or higher, allow at least fifteen minutes for the radiometer to adjust to the outside temperature.

Before going to the field to take readings, be sure the MSR.BAS program and current configuration/calibration is loaded in the DLC. Check that the Date, Time, Latitude, Longitude, and GMT Difference are correct for the location where you will be obtaining readings. This is more easily done using the TERMINAL program on a PC rather than using the smaller display of the CT100 Hand Terminal. Additional information and detail is available in the Operation section of the MSR User's Manual.

What follows below are the steps to obtain field plot readings.


  1. With the CT100 Hand Terminal connected to the DLC with the CT9M9M-5 cable, slide the CT100 Power switch to the ON position (Note: The CT100 gets its power from the DLC). The CT100 will flash some diagnostics characters on its display for a few seconds. When complete, the underscore character will be displayed in the upper left-hand corner of the display.

  2. Press the Enter key 3 times at approximately 1 second intervals. The following will appear and scroll upwards on the display:

    Copyright 1992-2002 by CROPSCAN, Inc.
    Copyright 1992-2001 by CROPSCAN, Inc.
    Enter or M-Menu

    The number of wavelengths shown depends on the radiometer model and how many channels are configured for RECORDing.

  3. Press Enter to proceed with the program.

    1 EVERY SS.
    2 AVERAGE SS.1

    Choose 1 to record every Sub-Sample per plot or choose 2 to record the average of the Sub-Samples.

    AUTO PLOT #s
    END PLOT#:80

    If automatic sequential plot numbering is configured. Any plot number may be chosen for the beginning plot number but the ending plot number cannot exceed 99999999. If manual plot numbering is configured, any plot number up to 99999999 may be entered. Spaces are ignored. After entering the beginning and ending plot numbers, the following information is displayed.

    R-Repeat scan
    P-repeat Plot
    D-Dark Reading

    P        1 S   1
    IRR  810 B 10.9

    The present plot (P) and plot sub-sample (S) numbers are then displayed on the first line. On the second line the real-time solar irradiance, IRR, and DLC battery voltage (B) are displayed.

    Note: If only down-facing sensors are being used then white reference panel readings will be necessary. Readings should only be taken on very clearsky days. It will be necessary to take at least one Dark Reading before taking any plot readings. To do this, press the D key. At the prompt, hold the dark (black) card against the bottom of the radiometer to block all light from the down-facing sensors. Press the Enter key after several seconds. Next, it will be necessary to take frequent white panel reference readings, perhaps once before every plot reading, depending on time of day (sunangle rate of change is least at solar noon and moreso earlier and later at larger sunangles). To do this, press the W key. Hold the radiometer level over a leveled white reference panel and press Enter, as prompted on the CT100 hand terminal display.

  4. Facing the sun, so as not to cast a shadow on the radiometer plot view area, position the pole to the desired spot over the first plot, tilting the pole so the bubble is centered and hence the radiometer leveled.

  5. Initiate a scan by pushing the space key or space bar or by pressing the hand-held manual scan push-button switch (optional accessory) momentarily.

    PLOT   1 SAMP  1

    The message ‘scanning...’ will appear on the screen. Simultaneously, an audible beep will be heard. When the scan is complete (about two seconds) two asterisks ‘**’ will be displayed and simultaneously, two beeps will be heard.

    PLOT   1 SAMP  1

    At this time, you can move to the next plot during which time the data is recorded and the word ‘Done’ appears. Simultaneously, three beeps will be heard.

    PLOT   1 SAMP  1

    After the scan is done, the next plot number or sample will be displayed to indicate that the system is ready for the next scan.

    PLOT   2 SAMP  1
    IRR  809 B 10.7

    Continue with step 4 above.

    To suspend operations after the plot number has been displayed (auto mode), or manually entered (manual mode), press the S key. The DLC will go to sleep and resume operations exactly where you left off upon a restart by pressing the Enter key three times. If you use the CT100 hand terminal, switch the power to OFF to reduce power drain until you are ready to resume operations.

  6. After the last plot scan has completed, press the 'M' key to return to the MSR Main Menu:

             MSR MAIN MENU
     1 Config-Status
     2 ReConfigure     7 Memory Card
     3 Retrieve Data   8 MSR Program
     4 Clear Data      9 Exit MENU
     5 View           10 BYE
    Enter Selection/Command

  7. Type 10 and press Enter to put the DLC to sleep:

    Returning to SLEEP... BYE!

    At this point, the plot readings have been made and the sensor millivolt readings logged in the DLC. The next step would be to RETRIEVE the data from the DLC to a PC file.

CROPSCAN, Inc. Home Page

1932 Viola Heights Lane NE
Rochester, MN 55906 USA
Phone: (507)285-9230

©2017 CROPSCAN, Inc.
all rights reserved