Analog Input object (AI)

'Present value' indicates the present value of the virtual variable.

Property ID: 85

'Tracking value' represents the uncorrected value as measured by the subsystem. It has the same data type as the 'Present value'.

• It is not limited by 'Present minimum value' and 'Present maximum value'.
• It is not corrected by the correction factor and offset.
• It is updated, even if "Out of service" = 'True' applies.

Property ID: 5107

"State flag" represents four boolean flags ("Out of service", "Overridden", "Fault", "In-Alarm") that indicate the general status of an object.

'Reliability' indicates whether the property value 'Present value' is reliable. If the 'Present value' is not reliable, the property 'Reliability' indicates the cause of the fault and the bit "Fault" of the state indication is set to 'True'. In a normal case, the property 'Reliability' is set to "No fault".

Property ID: 103

"Out of service" allows decoupling the object from being modified by a control program, system program or peripheral device.

• If "Out of service" is TRUE, the properties "Present value" and "Reliability" will no longer be updated by the respective control program, system program or peripheral device.
• If "Out of service" is TRUE, the properties "Present value" and "Reliability" can be modified for simulating and testing purposes.
• If "Out of service" will be changed from FALSE to TRUE, the properties "Present value" and "Reliability" keep their values. Nevertheless, they can be individually modified afterwards.
• If "Out of service" will be changed from TRUE to FALSE, the properties "Present value" and "Reliability" keep their values. They will be modified by the next update of the producer.

Property ID: 81

"Field device type" is a text description of the physical peripheral device connected to the input or output. Typically contains the product part number of the connected device. To be completed by the engineer. Is not used by the data acquisition.

Example: QAX3.P84 (room unit) - Entrance

"I/O address" identifies and documents the data source, and facilitates configuring, modifying, and querying the assignment in a standardized way.

The content of "I/O address" is technology-specific and includes:

• Unique selector to identify and document the respective data acquisition. For example, TX-I/O or KNX PL-Link.
• Unique address to identify the peripheral data source. For example, TX-I/O 3.4.
• Blank until assigned to a Module.

"Commissioning state" is an enumerated value representing the commissioning state (Not checked, Check failed, Check successful) of the BACnet object.

Typically set during commissioning by means of engineering and commissioning function (for example, Automation Building Tool or installer tool). It can be inspected by engineering and commissioning, or operation and monitoring functions, and used in commissioning reports.

"Commissioning information" indicates additional, human-readable information about the BACnet object's commissioning state. For example, "cable defect".

Typically set during commissioning by means of engineering and commissioning function (for example, Automation Building Tool or installer tool). It can be inspected by engineering and commissioning, or operation and monitoring functions, and used in commissioning reports.

"Update count" represents the number of times that the "Present value" property has been updated.

• "Update count" will be incremented whenever a value is written to the property "Present value".
• "Update count" will have a value equal to 1 as a default value after a download or object creation to indicate that the object has an initiated valid value.
• When the value of "Update count" reaches its maximum possible value, the next value it takes will be one (wrapping to 1).
• A control program can recognize that the same or a new value has been written to the "Present value" property by reading the current value of "Update count" and comparing it with the previously saved value of "Update count".

'Units' displays the physical unit of 'Present value'.

Property ID: 117

'Resolution' indicates the accuracy that a value represents. It defines the smallest recognizable change in engineering units of the property 'Present value' and be modified online.
'Resolution' is typically used for operating and monitoring functions to represent the 'Present value':
'Resolution' can only be an integer > 1.
'Resolution' is only used for an abbreviated depiction on the display, e.g. a station for operating and monitoring. It is not used to shorten the actual value that is processed by the program.

Property ID: 106

'Present maximum value' sets the highest value for the present value. Values greater than the configured maximum value are limited to the maximum value.

Property ID: 65

'Present minimum value' sets the lowest value for the present value. Values less than the configured minimum value are limited to the minimum value.

Property ID: 69

"Correction offset" serves to correct a potential difference between the real physical variable and the measured value. An additive factor.

"Correction factor" serves to correct a potential difference between the real physical variable and the measured value. A multiplicative factor.

'Change of value, COV' specifies the minimum change in 'Present value' property that will cause a COV notification to be issued to change-of-value subscribers of this object.

Property ID: 22

"Subsystem" uniquely identifies the respective BACnet object type extension of a BACnet object type.

Several BACnet object type extensions might be available for Engineering thus proposed for selection. None or one extension might be selected, thus be supported at runtime.

"Object access level" defines the instance-specific object access level. "Object access level" is used for generic filtering and processing an object by a client application.

• "Object access level" is a configuration property which can only be set up offline (ABT, application configuration).
• "Object access level" is evaluated by client applications such as Technical Operator, DB-Import, and APOGEE Point Team mapping.

Access level

Name

Description

7

Basic operation

Access to BACnet objects and properties for a room user e.g. data points visible on a room unit.

6

Standard operation

Access to BACnet objects and properties for standard operation and monitoring (daily business), .e.g. room and plant information on a management station.

5

Extended operation

Access to BACnet objects and properties for extended operation and monitoring such as network and device objects. All I/Os are visible

4

Administrator

Not used by HQ solutions yet.

3

Basic service

Access to BACnet objects and properties used for commissioning, e.g. configuration value extensions, I/O extensions, etc.

2

Extended service

Not used by HQ solutions yet.

1

Internal

Access to all BACnet objects and properties for very specialized actions e.g. during development.

"Object usage" indicates whether the object is used or unused. The "Object usage" property can hide or display respective objects and their functionality in a client. For example, room functionality can be marked for flexible room arrangements as used/unused. An object that is marked as unused behaves as if the object does not exist.

Property ID: 4930

"Event state" provides a way to determine if this object has an active event state associated with it. The "Event state" property indicates the event state of the object. Changes in the "Event state" property to the value FAULT are considered to be fault events. If the object does not support intrinsic reporting, then the value of this property is NORMAL.

Property-ID: 36

"Description" is a string of printable characters whose content is not restricted.

"Object name" represents a name for the object that is unique internetwork-wide. The minimum length of the string is one character. The set of characters used in the "Object name" are restricted to printable characters.

"Object identifier" is a numeric code that is used to identify the object. It must be unique internetwork-wide.

"Object type " indicates membership in a particular object type class. E.g. "Analog input", "Binary output", "Event enrollment", "Trend log", etc.

"Building automation profile" is an enumeration that indicates a particular type of Siemens proprietary object. Siemens objects are based on standard BACnet objects. For example, Siemens Analog Input, Analog Output, Analog Calculated Value, and Analog Configuration Value are based on standard Analog Input, Analog Output, and Analog Value BACnet objects.

"Profile name" indicates the name of an object profile to which this object conforms. To ensure uniqueness, a profile name must begin with a vendor identifier code followed by a dash. All subsequent characters are administered by the organization registered with that vendor identifier code. The vendor identifier code that prefixes the profile name indicates the organization that publishes and maintains the profile document named by the remainder of the profile name.

A string of printable characters whose content is not restricted.