First, use method
1 Select the light source, select the standard box to open the instrument box cover, select a suitable uniform light source, (such as indoor and outdoor sky scattered light or uniform light), the requirements of the same brightness of the bright surface point (this instrument should be able to meet the minimum illumination can be adjusted to zero, the largest The illuminance is to eliminate LOBAT1999 flashing on the instrument display. When the zero adjustment knob does not eliminate the flashing 1999, the illumination intensity must be reduced.)
According to the size of the area to be measured, the appropriate standard frame is selected. The closer the measured area is to the standard frame, the higher the measurement accuracy is, and the smaller the standard frame is, the stronger the illuminance is.
2WDY-500A use method
500A standard frame single measurement:
Press the power switch, the instrument displays 500 (the instrument defaults to 500 standard frames, the unit is cm2, memory is zero), press the zero key, the instrument displays a random number, adjust the coarse zero adjustment knob, fine tune the zero knob, make the instrument display 000 The standard area is placed on the measurement board. If the measured value does not meet the measurement error requirements in the technical parameters, the position of the instrument must be readjusted and re-tested. If the requirements are met, the measured object can be placed on the measurement board and the pressure plate can be placed. The instrument displays 210cm2, which is the measured area value of the measured object. (The actual calculation method of S is described later.) The 500A standard box performs multiple summation measurements. When the area to be measured is larger than the measurement board, a method of dividing the sum of multiple blocks is used. On the basis of a single measurement, the instrument displays a measurement area of ​​210cm2, press the measurement key, the instrument displays LOBAT210, press the memory (M+) key, the instrument displays the flashing 11 characters, and the memory is complete. Press the zero key again, the instrument displays a random number. After adjusting the zero point, place the measured object on the measurement board. The instrument displays the measurement result 198cm2. Press the measurement key, the instrument displays LOBAT198cm2, press the memory (M+) key, the instrument display flashes The 11 characters, at this time, the measurement results are stored again.
The instrument measures multiple times of storage, and only presses the RM key to display the stored results. If the stored result does not exceed 999, the instrument directly displays the result; if it exceeds 999, the monitor only displays two digits of LOBAT13.
Press the RM button once again to display the 084 three-digit value. The actual storage result 13084 is the S measurement value for multiple measurements. (The actual calculation method of S is described later.) When the storage value exceeds 65535, the display shows 88 flashing characters, indicating that the storage overflows at this time. Press the RM button to read out the saved result before proceeding with the next time. measuring. At this point, the result of the reading is not stored until the previous measurement result was flashed. If you want to continue to measure and store the measurement results, you must press the RST key to clear the memory before proceeding.
How to use 500A type, 300A type standard frame
WDY-500A instrument default 500, do not add the standard frame, press the zero key, adjust with coarse, fine zero adjustment knob, the instrument displays 000 can be measured, the specific measurement method is described in the fourth.
Press the full-scale value selection key 300 once and place the corresponding 300 standard box. The zero adjustment method is the same as the 500 box.
Press the second full-scale value selection key to display 150 and place the corresponding 150 standard frame. The zero adjustment method is the same as the 500 frame.
Press the full-scale value selection key three times to return to the default 500 box.
WDY-300A instrument default is 300, without adding a standard frame, press the zero key, adjust with coarse, fine zero adjustment knob, the instrument displays 000 can be measured, the specific method refers to four.
Press the full-scale value selection key once to display 150 and place the corresponding 150 standard boxes. The zero adjustment method is the same as the 300 box.
Press the secondary full-scale selection key to return to the default 300 box.
Whether in the WDY-500A or WDY-300A instrument measurement, if you want to change the standard frame, you must press the reset (RST) key, you can re-select, and at the same time, the memory content is cleared.
Second, regarding the measurement of the light-transmitting area, crop leaves that are not light-transmitting or light-transmitting are considered to be S-score=S. If the crops transmit more light, S-measures must be carried out. Calculations.
1 Find the Transmittance of Translucent Objects Place a standard frame on the measurement board, cover it with a light-transmissive object, and read the value of the display. For example, if a standard frame of 150 is used and the leaf area of ​​a light-transmissive object is completely covered, its reading is 144 (or other value).
If a 150 standard frame is covered with an impervious object, the reading should be 150. The formula for calculating the transmittance is as follows:
η=(S mark-S measurement)/S measurement×100%
η - transmittance of light-transmitting objects
S mark - the area covered by the standard frame or the standard frame that is completely covered by opaque objects
S real = S measurement × (1 + η)
S actual - actual area value of light-transmissive objects such as: When measuring soybean leaf area at a certain location:
S measurement = 98 square centimeters η = (100-98)/98 x 100% = 2.0408%
S real = 98 × (1 + 2.0408%) = 99.99 square centimeters If the crop is measured in the above case S is 139
It is real = 139 × (1 + 2.0408%) = 141.837 square centimeters
2 The instrument measures the area of ​​various light-transmitting objects Due to the plants and crops under various climatic conditions in various regions, the thickness of the leaves is different at each stage of growth. Therefore, the light transmittance is also different. When measuring the surface area of ​​a certain light-transmitting blade, the light transmittance of the blade should be measured first, and then the measurement of the light-transmitting crop should be performed. The actual value of S can be counted one at a time, or the sum of multiple measurements can be used to calculate the true value. value.
Third, the use of matters needing attention
1The instrument works in the environment of °C～40°C
2 try to use uniform, stable light source
3 is suitable for single person single work
4In the measurement process, the instrument should always calibrate the zero point
5 Turn off the power switch when the instrument is not in use. When the instrument shows flashing 000, the power is insufficient and a new battery must be replaced.
To replace the battery: Unscrew the two screws on the instrument battery plate, remove the battery plate, and install two 9v batteries.