How long should a single measurement with the CI-340 take in differential photosynthesis mode?

There is a single CO2 IRGA in the CI-340, this means that the instrument first must measure the CO2 level at the intake and then it switches over to measure the CO2 exiting the leaf chamber. The analyzer measures the intake for approximately 20 seconds, first. These measurements are sent to a microprocessor that averages these readings and corrects them for any non-linearity present in the analyzer. A relative value of CO2 concentration is continually updated by the microprocessor. The time interval set by the user at the beginning of the measurement dictates how long the measurement is taken and the concentration then averaged by the microprocessor. This time set by the end user is typically 10-20 seconds. Finally, the CO2 exiting the leaf chamber is measured by the analyzer for 20 seconds. This means that a complete single measurement takes approximately 45-60 seconds.