e. Measurement Process.
(1) Zeroing. When the balance is released at zero, the output voltage VO from the
LVDT is converted to a frequency fO by the V/F converter. This frequency is
measured for 0.2 seconds and the count is stored in the Z-register when the ZERO
button is operated. (Momentary contact).
(2) Ranging (calibration). Without changing the zero, a standard one gram weight
is placed on the pan. The output voltage VR from the LVDT is converted to
frequency fR and measured for 0.2 seconds. The zero count obtained in e.(1) is
subtracted from this count and the difference is stored in the R-register as R-Z.
(3) Measuring. The output of the LVDT during a measurement will be a voltage
and counted for 0.2 seconds. The number in the Z-register obtained in e.(1) is
subtracted from this count and the difference is stored as X-Z in the X-Z register.
(1) Zero. The balance is zeroed by releasing the beam with the pan empty, waiting
until the reading is steady and depressing the ZERO button momentarily. In
approximately 3 seconds, the balance indication will be .000-IN RANGE.
If there are disturbances to the pan, the indication may vary 1 digit and the
number displayed may be .XXX-UNDER; .000-IN RANGE; .001-IN RANGE. In
the case of minus indications (.XXX-UNDER) the digits are not significant.
g. Weighing Technique.
(1) Some basic principles fundamental to all types of precision weighing must be
observed in order to achieve the high precision of which the Voland Jupiter
J5000S is capable. Maximum precision is achieved when the balance and the
weights under test are at temperature equilibrium and the air inside the case is free
Disturbing elements which interfere with either of these will detract from
precision. To assure maximum precision the following procedure should become
standard operating procedure in any weighing sequence.
(2) To ascertain that the temperature of the weights is the same as the temperature
of the balance, it is best to store the sample and standard weights within the
balance chamber for at least one hour for the larger weights. With the door of the
balance closed, the weights, and balance can come to equilibrium together.
(3) Setting of Dial-Operated Weights.
The value of the weight under test must be dialed into the digital display in order
for the weight to be on-scale. In the case of metric weights, the indicated value of
the weight can be set directly on the dials. For instance, if the weight to be tested
is a 2 kg weight, merely set the 1 kg knob until the indicator (16) reads 2000. In