Trend Screen - York YK-EP Operation And Maintenance Manual

Trend screen

Figure 65: Trend screen
As many as six Operator selected parameters (Data Points) can be plotted in an X/Y graph format.
The X-Axis is scaled per the selected Data Collection Interval and displayed in a time of day
or elapsed time format, as selected with the X-Axis TOGGLE key. The Y-Axis is scaled for each
parameter per the selected minimum and maximum value for each parameter. Analog parameters
are scaled in pressure, temperature, volts, amps, hertz or time. Digital on/off parameters are
scaled as zero (off) and one (on). Only one Y-Axis label is displayed at a time. The Y-Axis TOGGLE
Key is used to toggle the Y-Axis labels through the different parameters. The Y-Axis label that is
being displayed is identified at the top of the graph. For identification, each plotted parameter and
associated Y-Axis labeling is color coordinated.
The DATA SELECT key is used to display all trended Data Points simultaneously or select a single
Data Point for display. The parameters are sampled at the selected Data Collection Interval and
plotted using 450 data points across the X-Axis. If the actual value of the sampled parameter is less
than the Y-Axis label minimum for that parameter, the value will be plotted at the minimum value.
Similarly, if the actual value is greater than the Y-Axis label maximum for that parameter, the value
will be plotted at the maximum value.
There are three types of charts that can be created: One Screen, Continuous or Triggered.
When plotting reaches the end of the X-Axis, if one screen is selected, trending stops and data is
frozen. If continuous is selected, the oldest data is dropped from the left-hand side of the graph
at the next collection interval. Thereafter, the oldest data is dropped from the left hand-side of the
graph at each data collection interval. If triggered is selected, data collection can be set to start
or stop based upon the selected Trigger Action (start or stop). If start is selected, data collection
will not begin until the triggers have been satisfied and any selected trigger delay has elapsed.
Data collection will stop at the completion of one screen of data as with the one screen. If stop is
selected, data collection will not stop until the triggers have been satisfied and any selected trigger
delay has elapsed.
176 YK-EP Style B Centrifugal Chiller