7.4 Calibration Verification: Genius
The Genius is constructed using solid-state electronics with surface-mount components for durability and
reliability. The only moving part in the probe is the RELEASE button assembly, which provides for long service
life. There are no electronic adjustments available to the biomedical engineer. All calibration is performed
digitally and is stored in nonvolatile EEPROM.
7.5 Recommended Calibration Interval
The Genius is constructed with components selected for their extremely low long-term drift characteristics.
Furthermore, two burn-in cycles during manufacture ensure that calibration drift will be minimal. However, all
electronic components exhibit some degree of drift, over time. To ensure accuracy to specification, Sherwood
I.M.S. recommends calibration of your Genius every 12 months.
7.6 User Calibration
Factory Calibration vs. User Calibration
The user is given the ability to check system calibration at two set-points (approximately 98ºF and 102ºF) and has
the option of adjusting the calibration in the field, by the entry of a “constant offset” into the calibration memory.
If the system calibration cannot be corrected to specification with this simple adjustment, it will have to be
returned to the factory where the entire calibration curve will be checked and recalculated. In most cases,
however, the simple “offset” adjustment in the field is all that is required to bring the system calibration back into
American Society for Testing and Materials (A.S.T.M.) specifications.
7.7 Calibration Sources
Because the Genius is an “optical” thermometer, not a “contact” thermometer, it must be stressed that all
conventional methods which would be used to check calibration on a “contact” thermometer do not apply and, in
fact, could seriously damage this thermometer. The importance of using a proper “blackbody” radiator as the
only type of calibration source cannot be over-emphasized. Furthermore, because of the unique shape of the
head of the Genius probe, it is not possible to rely on some “commercial” infrared calibration devices, or devices
provided for other infrared thermometers.
Acceptable Calibration Sources
1. Sherwood Medical Model 3000A-CL electronic calibrator.
2. Specially designed “blackbody adapter” (available through Sherwood Medical, ask for Part # 3000A-BB).
This blackbody adapter is designed to be used with an electronically controlled water bath and NBS
traceable probe. Instructions are shipped with the device.
Unacceptable Calibration Sources
1. Model 2000A-CL electronic calibrator: the shape of the calibration cavity is such that the Genius will not
properly fit into the device.
2. An ear: because of “emissivity” and “draw-down” problems the ear is inappropriate to use as a calibration
“device”. (See Sections 6 for explanations of “emissivity” and “draw-down.”
7-10