21
AS (Aperture Stop) PRESET Switch Setting (Fig. 30)
}The AS PRESET switches ² are used to preset the AS (aperture stop) value for each objective so that the opening of the
aperture iris diaphragm can be switched in an interlocked operation to the objective switching.
In the darkfield observation, the aperture iris diaphragm is fixed automatically at the open position.
The positions of the AS PRESET switches can be changed while the main switch is set to “
” (ON).
Setting the AS values
Insert a flat-blade precision screwdriver into the AS PRESET switch ² corresponding to the number of the objective
mount thread accommodating the desired objective, and turn the switch so that its arrow points the desired AS value.
(See Table 1 for the recommended values.)
AS interlocking
· When using the U-HSTR2 hand switch:
When the objective switching button on the hand switch is pressed, the objective is switched and, at the same time, the
AS value is set to the value set for the new objective. If the AS switch position is changed while the main switch is set to
“ ” (OFF), the new AS value will be applied to each objective after the main switch is set to “
” (ON).
· When using computer control through the serial interface (RS-232C):
When the request command (1OBA n) is input, the objective is switched at the same time as change of the AS
value to the set value.
Table 1 Recommended Settings of the AS PRESET Switches (Positions marked ¦)
(Note) The factory settings are all 0.
AS
PRESET
Switch
Setting
MPLFLN/UMPlanFl Series
MPLFLN-BD/UMPlanFl-BD/MPlanFl-BD Series
LMPLFLN/LMPlanFl Series
LMPLFLN-BD/LMPlanFl-BD Series
UMPlanApo Series
UMPlanApo-BD
Series
5X
10X
20X
50X
100X
5X
10X
20X
50X
100X
150X
250X
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
Not used
Not used
(Notes)
· The recommended AS values correspond to between 70% and 80% of the objective
pupil diameters. As a result, if the aperture iris diaphragm is stopped down below the
recommended value (toward “D”), the observation image will be glaring.
· When using an objective not in the objective list, set the objective pupil diameter at 70%
to 80%.
· Setting “0” inhibits the interlocked change of the AS value. Although the switch setting is
set at “0", the AS value becomes open when brightfield observation is switched to darkfield
observation. On the contrary, the AS value remains open when darkfield observation is
switched to brightfield observation.
· With fluorescent light observation, set the AS value to “1” (AS open).
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AS interlocking not available
Open AS
Close
AS
