Schedules in BAC0¶
Schedules object in BAC0 are supported by using two specific functions
bacnet.read_weeklySchedule(address, instance)
# and
bacnet.write_weeklySchedule(address, instance, schedule)
This is required by the complexity of the object itself which is composed of multiple elements.
First, as you notice, actually, BAC0 support the “weeklySchedule” which is a property of the bacnet object ScheduleObject. The exceptionSchedule is not yet supported. Neither the calendar.
The weeklySchedule property is generally used locally inside the controller and is often synchronized from a supervisory controller if required.
weeklySchedule are made of 7 DailySchedules. Thoses schedules are made from lists of events written as TimeValues (a time of day, a value to be in).
This level of nesting would be very hard to write as a string to be passed to bacnet.write so this is why we provide 2 specific functions.
Python representation¶
One challenge in BAC0 is finding a good way to represent a BACnet object in the terminal. With schedules, the challenge was the quantity of elements important to understand what is going on with the schedule, what are the events, what is the actual value, the priorityForWriting, etc… Important informations when you interact with a controller. But also, we needed a simple format allowing easy editing to be written to the controlle.
The dict was simple enough to hold all the information and the chosen format is
schedule_example_multistate = {
"states": {"Occupied": 1, "UnOccupied": 2, "Standby": 3, "Not Set": 4},
"week": {
"monday": [("1:00", "Occupied"), ("17:00", "UnOccupied")],
"tuesday": [("2:00", "Occupied"), ("17:00", "UnOccupied")],
"wednesday": [("3:00", "Occupied"), ("17:00", "UnOccupied")],
"thursday": [("4:00", "Occupied"), ("17:00", "UnOccupied")],
"friday": [("5:00", "Occupied"), ("17:00", "UnOccupied")],
"saturday": [("6:00", "Occupied"), ("17:00", "UnOccupied")],
"sunday": [("7:00", "Occupied"), ("17:00", "UnOccupied")],
},
}
schedule_example_binary = {
"states": {"inactive": 0, "active": 1},
"week": {
"monday": [("1:00", "active"), ("16:00", "inactive")],
"tuesday": [("2:00", "active"), ("16:00", "inactive")],
"wednesday": [("3:00", "active"), ("16:00", "inactive")],
"thursday": [("4:00", "active"), ("16:00", "inactive")],
"friday": [("5:00", "active"), ("16:00", "inactive")],
"saturday": [("6:00", "active"), ("16:00", "inactive")],
"sunday": [("7:00", "active"), ("16:00", "inactive")],
},
}
schedule_example_analog = {
"states": "analog",
"week": {
"monday": [("1:00", 22), ("18:00", 19)],
"tuesday": [("2:00", 22), ("18:00", 19)],
"wednesday": [("3:00", 22), ("18:00", 19)],
"thursday": [("4:00", 22), ("18:00", 19)],
"friday": [("5:00", 22), ("18:00", 19)],
"saturday": [("6:00", 22), ("18:00", 19)],
"sunday": [("7:00", 22), ("18:00", 19)],
},
}
Note
Those examples are all available by calling bacnet.schedule_example_analog or bacnet.schedule_example_binary or bacnet.schedule_example_multistate. This make a quick way to get access to a template.
Missing informations¶
Those templates, are simple models to be edited and should be used to write to schedules. But when you read weeklySchedule from a controller, you will notice that more information will be retrieved.
No worries, you can take what’s coming from the controller, edit the week events and send it back. When writing to a weeklySchedule BAC0 will only use the states and week element of the dict.
Example of a weeklySchedule from a controller
{'object_references': [('multiStateValue', 59)],
'references_names': ['OCC-SCHEDULE'],
'states': {'Occupied': 1, 'UnOccupied': 2, 'Standby': 3, 'Not Set': 4},
'reliability': 'noFaultDetected',
'priority': 15,
'presentValue': 'UnOccupied (2)',
'week': {'monday': [('01:00', 'Occupied'), ('17:00', 'UnOccupied')],
'tuesday': [('02:00', 'Occupied'), ('17:00', 'UnOccupied')],
'wednesday': [('03:00', 'Occupied'), ('17:00', 'UnOccupied')],
'thursday': [('04:00', 'Occupied'), ('17:00', 'UnOccupied')],
'friday': [('05:00', 'Occupied'), ('17:00', 'UnOccupied')],
'saturday': [('06:00', 'Occupied'), ('17:00', 'UnOccupied')],
'sunday': [('07:00', 'Occupied'), ('17:00', 'UnOccupied')]}}
As you can see, more information is available and can be used.
How things work¶
The ScheduleObject itself doesn’t give all the information about the details and to build this representation, multiple network reading will occur.
object_references¶
The ScheduleObject will provide a list of Object property references. Those are the points inside the controller connected to the schedule.
references_names¶
For clarity, the names of the point, in the same order than the object_references so it’s easy to tell which point is controlled by this scedule
States¶
BAC0 will read the first object_references and retrieve the states from this point. This way, we’ll know the meaning of the integer values inside the schedule itself. “Occupied” is clearer than “1”.
When using an analog schedule. States are useless as the value will consists on a floating value. If using an analog schedule, states = ‘analog’.
When using binary schedules, BAC0 will consider fixed states (standard binary terms) [‘inactive’: 0, ‘active’ : 1]
reliability¶
This is the reliability property of the schedule object exposed here for information
priority¶
This is the priorityForWriting property of the schedule. This tells at what priority the schedule will write to a point linked to the schedule (see object_references). If you need to override the internal schedule, you will need to use a higher priority for your logic to work.
PresentValue¶
Lnowing the states, BAC0 will give both the value and the name of the state for the presentValue.
week¶
This is the core of the weeklySchedule. This is a dict containing all days of the week (from monday to sunday, the order is VERY important. Each day consists of a list of event presented as tuple containing a string representation of the time and the value
{'monday': [('00:00', 'UnOccupied'),('07:00', 'Occupied'), ('17:00', 'UnOccupied')],
'tuesday': [('07:00', 'Occupied'), ('17:00', 'UnOccupied')],
'wednesday': [('07:00', 'Occupied'), ('17:00', 'UnOccupied')],
'thursday': [('07:00', 'Occupied'), ('17:00', 'UnOccupied')],
'friday': [('07:00', 'Occupied'), ('17:00', 'UnOccupied')],
'saturday': [],
'sunday': []}}
Writing to the weeklySchedule¶
When your schedule dict is created, simply send it to the controller schedule by providing the address and the instance number of the schedule on which you want to write
bacnet.write_weeklySchedule("2:5", 10001, schedule)