[R_B] Read binary

Function block R_B reads the present value and additional properties of a binary data point.

R_B reads the present value and additional properties of a binary data point.

Functioning

Compatible data points:

  • Binary input [BI]
  • Binary output [BO]
  • Binary, calculated value [BCalcVal]
  • Binary configuration value [BCnfVal]
  • Binary process value [BPrcVal]
  • Third-party objects with the required properties

Required properties:

  • Present value
  • Status flag

Optional properties:

  • Reliability
  • Update count
  • Extension by event configuration
  • Event state
  • Acknowledged transitions
  • Extension by data aggregation
  • Maintenance state
  • Operating hours
  • Suppress event notification
  • Suppress event detection
  • Enable aggregation
  • Enable substitution value
Pins

Input

Description

Data type

Default value
Value range

SupEvtDet

Suppress event detection

Suppresses the detection of events.
Note
If the extension for 'Intrinsic reporting' is not enabled, the input value is not considered in the function of the function block.
If the same BACnet object is accessed by multiple functions in a control program, only one of these function blocks may interconnect to the pin.
The function is not available for BACnet third-party objects.

Boolean

0

SupEvtNtf

Suppress event notification

Suppresses notification of events.
Note
If the extension for 'Intrinsic reporting' is not enabled, the input value is not considered in the function of the function block.
If the same BACnet object is accessed by multiple function blocks in the control program, only one of these function blocks may interconnect to the pin.
The function is not available for BACnet third-party objects.

Boolean

0

EnDataAgn

Enable data aggregation

Permits activation or deactivation of data aggregation.
Note
If the extension for data aggregation is not enabled, the input value is not considered in the function of the function block.
If the same BACnet object is accessed by multiple blocks in the control program, only one of these function blocks may interconnect to the pin.
The function is not available for BACnet third-party objects.

Boolean

0

BaObjRef

BA-Object reference
Link between function block and BACnet object.

Structure

---

BaObjRef
> DeviceID

Device identifier
[DeviceID] includes object type and object instance in one ID.
Identifies the device object: local or remote. A local device object can also be identified by value 16#3FFFFF.

Double Word

16#3FFFFF

BaObjRef
> ObjectID

Object identifier
[ObjectID] includes object type and object instance in one ID.
Identifies the object on a device.

Double Word

16#3FFFFF

BaObjRef
> ItemID

Item identifier
[ItemID] represents an index in a view node object that references the BACnet object.
[ObjectID] and [ItemID] together define an indirect reference to the BACnet object.
Value -1 indicates a direct interface.

Integer

-1

 

Output

Description

Data type

Default value
Value range

PrVal

Present value

Value of property 'Present value' for the referenced BACnet object.

[PrVal] supplies the last valid value in the event of a fault unless the property 'Enable substitution value' is available for the BACnet object and indicates that the substitution value should be used.

Note
The default initial value for [PrVal] can be changed to another value in the programming editor as needed.

Boolean

0

UpdInd

Update indication

Boolean

0

Indicates if the property 'Present value' has been updated.

Upon updating, [UpdInd] goes from 0 to 1 and returns to 0 in the next cycle (immediately). Changeover cannot be detected without additional function block connected to [UpdInd] (e.g. counter function block). [UpdInd] is only set to 1 if the BACnet object is not in fault.

[UpdInd] uses property Update count, if available. This allows for detecting if a value was updated when the new value equals the previous value. In objects without update count, [UpdInd] changes over to property Present value in case of a change.

Dstb

Disturbed

[Dstb] indicates whether the referenced BACnet object is in fault or in state OffNormal. When the BACnet object returns to state Normal, [Dstb] retains its value until the transition to normal is acknowledged.
[Dstb] = 1, if:
BACnet object = Access error
OR
'Status flag' = Fault
OR
'Update count' = 0
OR
'Event state' <> Normal

[Dstb] = 0, if the above condition is not fulfilled AND 'Acknowledged transitions' = x, x, 1.

Note
Properties 'Event state' and 'Acknowledged transitions' are not considered if the BA-Object has an alarm extension set to disabled.
Output [Dstb] does not retain the value after a restart following a power outage if the state of the BACnet object is normal.
Properties 'Event state' and 'Acknowledged transitions' are not considered on BACnet third-party objects.

Boolean

0

Flty

Faulty

[Flty] indicates whether the last event on the referenced BACnet object was in fault. If the BACnet object returns to the normal state, [Flty] retains its value until the transition to normal is acknowledged.
[Flty] = 1, if:
BACnet object = Error during access
OR
'Status flag' = Fault
OR
'Update count' = 0

[Flty] = 0, if the above condition is not fulfilled AND one of the following possibilities is valid:

  • 'Event state' = Offnormal
  • OR
  • 'Event state' = Normal AND 'Acknowledged transitions' = x, x, 1

Note
Properties 'Event state' and 'Acknowledged transitions' are not considered if the BA-Object has an alarm extension set to disabled.
Output [Flty] does not retain the value upon restart after a power outage if the state of the BACnet object is normal.
Properties 'Event state' and 'Acknowledged transitions are not considered for BACnet third-party objects.

Boolean

0

OffNrml

Offnormal

[OffNrml] indicates whether the last event on the reference BACnet object was Offnormal. When the BACnet object returns to state Normal, [OffNrml] retains its value until the transition to normal is acknowledged.
[OffNrml] = 1, if:
BACnet object = Access successful
AND
'Status flag' = No fault
AND
'Update count' > 0
AND
'Event state' = Offnormal

[OffNrml] = 0, if the above condition is not fulfilled OR 'Event state' = Normal AND 'Acknowledged transitions' = x, x, 1.

Note
Properties 'Event state' and 'Acknowledged transitions' are not considered if the BA-Object has an alarm extension set to disabled.
Output [OffNrml] does not retain the value after a restart following a power outage if the state of the BACnet object is normal.
The function is not available for BACnet third-party objects.

Boolean

0

Rlb

Reliability
Indicates the value of property 'Reliability', if the property is available.

Integer

0: No fault detected

Oph

Operating hours

Displays the value of the property operating hours for the referenced BACnet object
Note
The output is set to 0, if the extension for data aggregation is disabled or the property does not exist. The function is not available for BACnet third-party objects.

Double Word

0

MntnSta

Maintenance state

Supplies the value for property 'Maintenance state' for the referenced BACnet object.

Integer

1

1: None
2: Limit present period exceeded
3: Limit exceeded

Note
The output is set to 1 if the extension for data aggregation is disabled or the property does not exist.
The function is not available for BACnet third-party objects.

ErrCode

Error code indication

Integer

0: No error

= 0 - No error
> 0 - XFB error codes