Graph Mode
Graph Mode will be entered automatically when the unit has stabilized in Sensor Stability mode. Or to enter Graph Mode, press the right arrow when the F-900 is at the Sensor Stability screen. This view graphically displays the measured C₂H₄ value over time. To switch Graph Mode into Monitor Mode, press the right arrow. To exit the measurement, press Stop.
Figure 11: Graph Mode with red arrow indicating direction of movement.
Directly below the graph is the current ethylene value. Above the graph is the dynamic range (on the left it is 1.000 ppm, on the right it is 2.000 ppm). The y-axis scale is set by the highest value shown in the buffer. This range will scale vertically, dependent on the highest concentration of ethylene measured. If the concentration is small, the dynamic range will reflect this. For example, the initial value was 0.162 ppm and there is a sudden peak to 7.578 ppm. As the spike or peak occurs, the graph will scale to 10.000 ppm. If the sample returns to 0.168 ppm, the scale will remain at 10.000 ppm until the graph and the buffer are cleared.
The scale of the graph can be increased or decreased by using the up and down arrows. Pressing the up arrow will zoom in on the data, minimizing the visible range. Using the down key will increase the scale, up to 200 ppm. Note that the minimum range of data visible (down to 0.150 ppm) depends on the current data being graphed. For example, if the current data is 3.486 ppm, the user may use the up key to zoom in to the 5 ppm range, but cannot zoom in to a narrower 2 ppm range.
The graph begins on the left side and moves with the vertical line towards the right as more data points are added. Once the time line reaches the right side of the display, the data will be compressed to the far left.
The time scale relates directly to the vertical position line. In other words, the line moves to the right as new data points are added. Every time a data point is added, the time scale is incremented. For time under 10 minutes, the graph is updating almost every second. The bottom of the display shows the uptime of the F-900 and current battery level.