Method and apparatus for verifying proper operation of a photometric device, such as a cell density probe

An article of manufacture comprising a photometric device that is usable for a light absorbance application, the article of manufacture comprising:

• a machine-readable medium having instructions stored thereon and executable by the processor to cause a processor to test the photometric device by:
• i) changing a signal supplied to a light source of the photometric device, the supplied signal usable to activate the light source to emit light;
• ii) obtaining a first signal representative of the light emitted from the light source;
• iii) obtaining a second signal representative of the light emitted from the light source after at least some of the emitted light has passed through an optical gap of the photometric device;
• and
• iv) determining whether the photometric device is operating properly based on a comparison between an obtained value, associated with either one or both of the first and second signals, and at least one reference value wherein the instructions executable by the processor are executed in-situ while the photometric device is deployed and substantially without interruption of operation of the photometric device and without regard to light absorbance in an optical gap of the photometric device.

A system, comprising:

• a photometric device including a light source for performing an optical absorbance determination comprising:
• i) means for changing a signal supplied to the light source, the supplied signal being usable to activate the light source to emit light;
• ii) means for obtaining a first signal representative of the light emitted from the light source;
• iii) means for obtaining a second signal representative of the light emitted from the light source
• iv) means after at least some of the emitted light has passed through an optical gap of the photometric device for determining whether the photometric device is operating properly based on a comparison between an obtained value, associated with either one or both of the first and second signals, and at least one reference value;
• v) means for communicating to and from the photometric device;
• vi) display means for presenting information related to operation of the photometric device;
• vii) user interface means for allowing user interaction with the photometric device;
• and
• viii) means for allowing the photometric device to be tested in-situ for a cell density application.

A photometric apparatus usable for a light absorbance application, the apparatus comprising:

• a light source that can supplied with a signal that can cause the light source to emit light;
• a first detector to detect a characteristic of the light emitted from the light source;
• a second detector to detect a characteristic of the light emitted from the light source after at least some of the light has passed through an optical gap;
• a processor to control application of the signal supplied to the light source, wherein the processor can determine whether a malfunction may exist if there is a predetermined difference between an obtained value, associated with either one or both of the first and second signals, and at least one reference value;
• means for communicating to and from the photometric apparatus;
• display means for presenting information related to operation of the photometric apparatus;
• user interface means for allowing user interaction with the photometric apparatus;
• and
• means for allowing the photometric apparatus to be tested in-situ for a cell density application.