W_BG: Write binary group

W_BG supports the distribution of Present value and Reliability properties (a "value/reliability pair") to a group of binary calculated value objects that share a specific group data tag. W_BG also supports the distribution of a value to a specific property of datatype Boolean, to a group of objects that share a specific group data tag.

Compatible data points:

Refer to data point objects for a detailed description of the BACnet data points.

 

Required properties:

 

Inputs

BaObjRef

BA-Object reference

Structure

[BaObjRef] defines a bound connection between XFB and BACnet object. The binding occurs automatically.

Manual configuration attempts are not necessary and can result in system errors.

DeviceId

Device identifier

Double word (default value: 16#3FFFFF)

[DeviceId] comprises object type and object instance in a single identifier.

It is used to identify device object: local or remote. Local device object could also be identified by value 16#3FFFFF.

ObjectId

Object identifier

Double word (default value: 16#3FFFFF)

[ObjectId] comprises object type and object instance in a single identifier.

It is used to identify object within a device.

ItemId

Item identifier

Integer (default value: -1)

[ItemId] represents an item index in the functional view node object, which references the BACnet object.

[ObjectId] and [ItemId] together define an indirect access reference to the BACnet object.

Value -1 indicates that direct binding is used.

GrpTag

Group data tag

Double word (default value: 0)

[GrpTag] defines the specific group data (present value, priority) for centralized distribution by the XFB.

The system provides predefined and also user definable tags. The [GrpTag] is typically set by the application developer in CFC and must not change during runtime. It must be set to a tag that matches the datatype of the XFB.

EnWrit

Enable write

Boolean (default value: True)

When True, [EnWrit] enables the inputs Val and SetValid to be written to the calculated value object.

Val

Value

Boolean (default value: False)

A virtual value calculated and assigned by the Control program to update Present value.

[Val] is used to update the Tracking value property, after which the BACnet object internally updates Present value with the written Tracking value.

If [EnWrit] is True, [Val] will be written if:

  • [Val] changes
  • [SetValid] changes
  • [RptWrit] is True

SetValid

Set valid value indication

Boolean (default value: True)

A value calculated and assigned by the control program that indicates whether [Val] is reliable.

[SetValid] maps to an error code that updates reliability if [EnWrit] is True and any of the following:

  • [SetValid] changes.
  • [Val] changes.
  • [RptWrit] is True.

1 (True)

Reliability error code 0 (no fault)

0 (False)

Reliability error code 7 (unreliable - other)

RptWrit

Repeat write

Boolean (default value: False)

[RptWrit] forces a write of inputs [Val] and [SetValid] to the data point. The write operation is repeated with each program cycle for as long as [RptWrit] is True.

[RptWrit] will typically be calculated and set by the control program.

Note:
[RptWrit] must not be forced permanently to True by connecting to a block output that is always True. Doing so will cause a high level of communication traffic.

1 (True)

If [EnWrit] is True, [Val] and [SetValid] are written to the data point with each program cycle for as long as [RptWrit] is True.

0 (False)
default

No action

 

Outputs

ErrWrit

Error while writing

Integer (default value: 20)

The error code value for errors encountered during accessing or writing to the group manager object.

Successful distribution of a command to group members cannot be indicated.

= 0

No error.

> 0

Error, see XFB error codes.