Fluke Biomedical 07-424 - Manual (Page 7)

Operation
Setup for Operation
2
2-1
Section 2
Operation
2.1 Setup For Operation
1. Remove the packing material and the tape that secures the measuring arm. Locate the two (2)
plastic envelopes that have been shipped with the instrument. The first contains one (1) #37 lamp,
and an o-ring. The second contains three (3) apertures; 1, 2 and 3 mm. Remove the apertures to
be used for measurement.
2. Plug the instrument into an appropriate receptacle. Voltage may vary from 100 to 130 V (200 to 260
V) without affecting the accuracy of the readings.
3. Turn the power switch to ON. The display should indicate all digits and the table should be
illuminated.
4. Place the 3 mm aperture in position under the photohead in the depression over the filter light
source WITH THE FLAT SIDE UP. Now press the arm down in firm contact with the aperture by
placing your hand on the PRESS HERE area of the arm. The display should read 0.010 to 0.20
(positive), with the ZERO control fully counter-clockwise. Now zero the unit by turning the ZERO
control clockwise until the minus sign (located just above the left hand digit) flashes on and off. This
indicates an exact zero condition.
2.2 Operation
1. Select the proper aperture (small flat side UP).
2. Set the ZERO control.
3. Place the film over the aperture with the emulsion side up.
4. Press down on the arm, as indicated, and read optical density on the digital display for high
densities and/or small apertures, it may take a second or two for the reading to reach equilibrium.
5. Density Subtraction: You may find the difference in two densities by turning the ZERO control so
that it reads zero (flashing minus sign) over one film area, then reading a second film area. The
relative density, positive or negative, of the second area measured, will be indicated on the display.
5. On all subsequent readings, check the ZERO before reading a density. While the zero drift is small,
a routine check prevents the possibility of an incorrect value, if, for example, the ZERO knob has
been accidentally disturbed.