You can easily make minor modifications such as adding or deleting calculations, or the system can be reprogrammed to add new features or enhancements. No hardware changes are required for software updates. Simply download software updates via the RS-232 port. This makes continued software development straightforward and guarantees that your LI-6400 will stay current. OPEN allows fully automatic and independent control of leaf chamber CO 2 and H 2 O concentrations.
Flow rate is controlled by pump speed in the standard system.
With the optional CO 2 injector, pump speed is constant and flow rate to the chamber is controlled by dumping off excess flow. In either case, the air supplied to the chamber may be dried or moist. Supplying the chamber with moist air allows higher flow rates to be used to balance low transpiration rates, which provides more stable control and more accurate measurements. Time delays related to water sorption in the air lines are minimized because the air stream humidity is set to a fixed value. The rate of pure CO 2 injection is varied according to demand from the leaf chamber, or from the input CO 2 setpoint, whichever approach you specify.