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The CO2 Sensor Simulator is a PC-controlled test device that plugs into any product utilizing the COMET CO2 Sensor (such as the CO2 Module).
It generates all the analog and digital signals necessary to be recognized as a
valid CO2 Sensor, and is capable of simulating various waveforms and CO2
concentrations.
The Simulator was designed to assist engineers in the
development, test, and validation of capnography-based products. One or two
Simulators can be controlled by the PC through the USB interface. The software
provides access to the following functions:
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generates capnography waveforms from text files
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generates capnography waveforms from manually selected CO2
concentrations
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introduces random respiration rates
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introduces random waveform amplitude
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introduces slow/wandering baseline
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generates apnea condition
The software displays the following information:
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CO2 waveform
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CO2 trend (latest three hours)
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End-of-Breath Parameters (etCO2, inCO2, RRavg, RR, Ti, Te)
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Start-of-Breath and End-of-Breath waveform markers
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Analog voltages
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Lamp and Valve status
Custom waveforms can be created in text files and played back
through the Simulator. These files can be designed in a spreadsheet or taken
from patient data files. Engineers can use the Simulator to test hardware and
software design integrity and test error conditions. Marketing can use the
Simulator for user training and demonstrations. Service personnel can check the
performance of returned goods or repairs.
Because the CO2 Sensor Simulator is PC-based, new test and
diagnostic features can be added in the future simply by a software upgrade.
When the SIMULATOR software is run and a Simulator Pod is
attached to the PC, the above screen is displayed. The user can select a
Waveform File to be used or any of the Manual selections. The STOP/START button
is used to begin waveform simulation. The lower Waveform screen displays the raw
waveform being simulated, and the upper Trend screen displays three hours worth
of etCO2/inCO2 trends. When the SIMULATOR is started, the CO2 Module may be
turned on.
The SIMULATOR software contains the same Breath Detection
Algorithm as the CO2 Module, and red and green markers on the waveform depict
the start-of-expiration and start-of-inspiration points respectively. RR, etCO2,
inCO2, Ti and Te are displayed for each detected breath.
When the SIMULATOR senses the solenoid valve of the CO2
Module turning on, it will automatically set the CO2 Sensor voltage level to
mimic 0% CO2, so that a valid offset calibration may be performed. This offset
calibration will not appear in the SIMULATOR Waveform screen or Trend Screen.
A gain calibration may be performed by selecting the
appropriate concentration gas (ie. 5.0% CO2) manually, and then prompting the
CO2 Module to initiate a gain calibration using the communication protocol
between the CO2 Module and the medical device user interface.
A number of functions can be applied to the simulated
waveform:
The user may manually create waveforms using Manual Scroll
Mode. When this mode is selected, moving the scroll bar control up and down
causes the simulated CO2 concentration to change accordingly.
Custom waveform files can be created with text editors or
spreadsheet programs. These files can be saved to the SIMULATOR application
directory with all the existing waveform files. Real patient waveforms
collected by the CO2 Module can be saved into files for later playback by the
SIMULATOR.
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