Object accumulator meter (AccMtr)

'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

"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.

"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

"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".

"Last update time" indicates date & time of the last update of present value. "Last update time" will be updated when a new present value is written.

"Prescale" defines the coefficients that are used for converting the pulse signals generated by the measuring instrument into the value displayed by present value.

These coefficients will be used to convert input pulses represented by tracking value into the value represented by present value.

BACnetPrescale includs the values Multiplier and ModuloDivide supporting non-integral ratios of measurement pulses to and present value.

Multiplier

The numerator of the conversion factor expressed as a ratio of integers.
Range: 1 .. 10000

1

Default

ModuloDiv

The denominator of the conversion factor expressed as a ratio of integers.
Range: 1 .. 10000

1

Default

Example:
In an electrical metering application, the output of the voltage- and current-measuring systems might be 9000/1200 (scale / voltage*current) pulses per kWh, requiring the Accumulator object to accumulate 2/15 kWh/pulse.

"Scale" defines the conversion factor to be multiplied with the value of preset value to provide a value in the engineering units indicated by units.
The scaling operation will be performed by the client display or process the value of Present-Value in engineering units indicated by the Units property.

BACnetScale
The choice of options for the property determines how the scaling operation has to be performed.

FloatScale

Flexible variable-point representation, not lossless representation

0

Real Present-Value * Scale

IntegerScale

Fixed-point representation, lossless display and processing

0

Integer Present-Value *10Scale

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

Property ID: 117

"Present maximum value" indicates the highest number in engineering units that can be reliably obtained for the "Present value" property of this object.

"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.

"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.