(2) into the preweigh (up) position (fig. 2-7). If the optical scale
does not indicate zero, adjust the zero control knob (1, fig. 2-6).
2. After the scale is zeroed, arrest the balance
by depressing the arresting lever to the arrest position (fig. 2-7).
Next check zero in the full-release position (fig. 2-7). Place the
arresting lever in the down position. Adjust the optical scale to
zero by using the zero control knob (1, fig. 2-6). If zero adjust-
ment cannot be made, refer to Chapter 3 for calbiration and mainten-
ance instructions. Place the sample on the pan, close the glass
doors and lift the arresting lever into the preweigh position. The
coarse weight will then be indicated on the optical scale, (5, fig.
2-6) . Set the weight control knobs to show the same weight on the
macroweight counter. Depress the arresting lever to the arrest
position and, after a brief pause (about 3 seconds), move the arrest-
ing lever to the full-release position. When the optical scale comes
to a stop, use the micrometer drum knob to move the scale pointer
(micrometer line) over the next lower optical division of the moving
scale. The readout can then follow from left to right: first the
macro values from the macroweight counter, then the first two decimal
places on the optical scale and the final two digits from the micro-
scale. Return the fine adjustment back to zero at the completion of
3. The taring capabilities of the balance can be
used on containers weighing less than 1 gram by first zeroing the
balance, and then placing the container on the pan. The reading on
the optical scale is the tare weight of the container. After taring,
if the container is to be filled with a specific weight, adjust the
zero control knob to reflect zero on the optical scale and proceed as
(a) Remove the container from the analyt-
ical balance and place it on the double beam balance. (Tongs should
(b) Tare the container on the double beam
balance. Add the tare weight and desired additional substance weight
mathematically to get an approximate total. Proceed to fill the
(c) After obtaining the approximate total
weight, remove the container from the double beam balance and place
it on the pan of the analytical balance. (Tongs should be used).
(d) Adjust the final total weight by use
of filter paper or a glass rod.
4. To tare containers over 1 gram, weigh the
container as noted for any unknown weight. After taring, if the
container is to be filled with a specific weight, adjust the zero
control knob to reflect zero on the optical scale and leave the
macro weight counter untouched. Follow steps (a), (b) and (c) in
paragraph 3. above, and, by use of filter paper or a glass rod,
adjust to the specific weight desired by accounting for the macro
weight figure only.