Accuracy Checking

Magnification Accuracy

NOTE: It must be stressed that the following is not part of the routine installation and servicing procedure.

This inspection instrument is designed to project an image within ±.10% on profile and ±.15% on surface illumination over the entire screen. Prior to shipment the unit is calibrated and certified to be well within this specification. If image accuracy of this magnitude is required on a daily basis by you, the customer, then an established calibration interval must be determined to meet your requirements.

Although the generally accepted calibration interval for this type of optical inspection equipment is 1 year; factors such as frequency of use, environment and duty may affect the ability of any instrument to remain in calibration. Calibration intervals must be adjusted up or down to compensate for these factors. If only one lens shows a magnification or distortion error, it is possible that adjustment is required to only the lens. Simply loosen the lens retaining ring and adjust the lens as required.
If magnification is not uniform over the entire screen then mirror adjustment will be required.

Consult a qualified/certified individual or organization to perform this task. It is considered to be out of the scope of the average user to maintain the proper calibration equipment and training required to accurately calibrate an optical instrument. Dorsey Metrology International OMD provides this service and also training classes on calibration. Consult us for details.

Readout Accuracy

The accuracy of your digital readout system is dependent on many items. Factors such as stage accuracy and condition, scale accuracy and condition and method of inspection will determine the outcome of any accuracy test. Although this is an operations manual and is not intended to serve as a calibration manual; we have outlined the basics of inspection and compensation below.

• Inspect condition of system and repair/ replace as required.
• Test mechanical repeatability and geometry of stage adjust as required.
• Test repeatability of scale-DRO, adjust, replace or return to step 2.
• Inspect accuracy of reading using a certified standard of known dimension.
• If reading is within specifications the procedure is complete.
• If reading is not within specifications, remove all compensation and re-inspect. Compensate as required per instructions with your separate digital readout manual.