Quantum Composers AF910 - Manual (Page 23)

AF910 Manual Version 1.4 Page 23
- Step Offset Function. This function will allow the motor to move any offset
distance when switching objective lenses. Since objectives may have different
focal lengths, this method will move the stage (using motor steps) a set
amount when switching lenses. The change disable command (CD) allows for
the switching of objectives and positioning the focus stage into a nominal
position before re-enabling the auto focus. Once this command is issued, the
auto focus will be disabled and the stage positioned into a nominal focus for
the next objective. This eliminates the need to manually adjust the focus stage
before re-enabling the auto focus if there is a variation in the focal lengths of
the objectives being used. Each objective number will have an associated
focus stage offset motor count. This will assure that the focus stage is
positioned within the auto focus’s capture range before it is enabled. Refer to
the command set section for detailed usage of the commands.
Figure 26
Procedure:
1. Select an objective as the reference objective. This will be the objective that
will have a zero step offset value to it (CO value).
2. Use the OB command to select the proper objective number. Example: select
OB 1 for the reference objective.
3. Focus the reference objective by moving the focus stage up and down using
the motor control commands.
4. Using the CO command, enter a value of 0 for the change offset. Take note of
the motor step position using the SC? command. Write this number down as
the reference position. This reference position will be used to calculate all the
other objective offsets.
5. Select the next objective to calibrate the step offset for. Change the objective
by using the OB command. Example: select OB 2 for the next objective.
6. Focus the objective using the motor control commands and take note of the
motor step position using the SC? command.
7. Subtract the reference objective motor step position from the new objective
focus position (New Position – Reference Obj Position = CO value). This will
be the value you enter using the CO command. This may be a positive or
negative offset depending on if the focus for the new objective was higher or
lower than the reference objective.
8. Repeat steps 5-7 for the next objectives. Be sure the change the objective
number each time using the OB command and recording the new objective
position and calculating the motor step difference between it and the original
reference objective.