M77781A
MS257
™ USB/RS232
MONOCHROMATOR AND SPECTROGRAPH
14
7 INSTRUMENT OPERATION
7.1 INSTRUMENT CONFIGURATION
The instrument configuration is maintained as a collection of parameters and values. Suitable
factory defaults are provided. The
Active Configuration
is the current setup. This is always
saved and restored when powering up the instrument.
Configurations can be saved and loaded in several ways:
To save the active user configuration and to reload the user configuration, one may use the
Hand Controller, the configuration software or a computer terminal program.
The instrument can be configured by Oriel Instruments to have calibrations saved on CD for more
than one grating turret, allowing the user to change the turret and load the appropriate
configuration information as needed.
Individual Grating Calibration
Each grating is precisely aligned on its mount or grating turret. However, small offsets or
calibration adjustments may be required for each grating. This calibration should be performed for
each port in use. The procedure is as follows:
1. Select a grating.
2. Select a source with prominent spectral lines for calibration purposes.
3. Use very small slit sizes. I using a diode array or CCD, use a small entrance slit.
4. Drive the grating to a spectral line such as a HeNe line at 632.8 nm or an Hg line at 546 nm.
5. Step the motor drive using the Hand Controller or MS257 programming language until the line
is centered at the output slit, or in the case of a diode array or CCD at the center pixel.
6. Use the
Calib
command on the Hand Controller or
CALWAV
command if using the terminal
program, and enter the correct wavelength for the spectral line.
7. The recalibration of the grating for that port is now complete.
8. Change the detector port using the Hand Controller or MS257 programming language if the
MS257 is equipped with an Output Flip Mirror. Never move the flip mirror manually.
9. Repeat the procedure for the other detector port if it is being used.
10. Repeat Step 1 through 9 for each grating on the turret.
Fine Focus Adjustment
In order to obtain the best optical performance, a fine focus adjustment feature is included. This
enables precise translation of the exit mirror to optimize the image onto focal plane detectors
such as diode arrays and CCDs. These accessories do not have a precisely known detector
positions, which is why the light may have to be focused to achieve best resolution. Note that
after refocusing, one may require a new spectral calibration.
