Echelon SmartServer 2.2 - Manual (Page 358)

SmartServer 2.2 User’s Guide 359
6. Create the exception schedules by setting the range of dates for which the exception schedules are
used by creating one-time exceptions, exceptions, and recurring exceptions, and creating events.
You can also create exception schedules in the Event Calendar and apply them to all the Event
Schedulers on the SmartServer.
Planning Your Schedule
Before using the Event Scheduler, plan your schedule to determine the schedules and events that need
to be created. The following example demonstrates a simple schedule for scheduling HVAC and
lighting controls in a retail store. In this example one preset is used to update data points in both the
HVAC and lighting controls.

On weekdays, the heat is set to 60°F at 7:00 AM (WARMUP); the heat is set to 70°F and the
lighting turned on at 9:00 AM (OPEN); the heat and the lighting are turned off at 6:00 PM
(CLOSE).

On weekends, the heating and lighting remain off.

For inventory (the last Sunday of each month), the heat is set to 65°F and the lighting turned on at
9:00 AM (OPEN_INVENTORY), and the heat and the lighting are turned off at 6:00 PM
(CLOSED). In this case, you need to create a recurring exception.

Every year you will have a winter vacation. In 2013–2014, the vacation is from December 22
nd
to
January 1
st
, but you may change the dates every year.
Configuring the Real-Time Clock
You can use the real-time clock on the SmartServer to schedule events to start or stop based on the
calculated sundown or sunrise, or a configured amount of time before or after the sundown or sunrise.
The real-time clock includes an astronomical position sensor that calculates the position of the sun
based on the time-of-day stored on the SmartServer and the location (geographic coordinates) of the
SmartServer, which you specify. Based on the calculated position of the sun, the real-time clock can
determine the sunrise and sundown times and pass this information to the Event Scheduler.
More specifically, the astronomical position sensor application in the SmartServer calculates the
elevation and azimuth of the sun relative to the location of the SmartServer and then stores the results
in its nvoElevation and nvoAzimuth SNVT_angle_deg data points. The elevation is returned as a
value between -90 and 90, where a positive value indicates that the sun is up and a negative value
indicates that the sun is down. The azimuth is returned as a value between 0 and 360, where 0
indicates that the sun is directly to the north, 90 indicates that the sun is to the East, 180 indicates that
the sun is to the South and 270 indicates the sun is to the West.
The following figure demonstrates how the elevation and azimuth are mapped to the sun’s location. In
this figure, the elevation of the sun is calculated to be approximately 60° and the azimuth is measured
to be approximately 290°, which means that the sun is up in the mid-afternoon and is located northwest
of the SmartServer. The calculated elevation and azimuth are stored in the nvoElevation and
nvoAzimuth data points.