CMD_LGTG: Command lighting group

CMD_LGTG distributes, at a particular priority, either a Present value (of datatype Real or BACnetBinaryPV) or a Control command (of datatype BACnet lighting command) to multiple analog or binary BACnet lighting output objects for a specific Group data tag. Both target state commanding and control command commanding are supported.

Proprietary objects are needed for grouping infrastructure: one Group manager object and one or more Group member objects. The individual member data points (the lighting output objects) are grouped and referenced via the Group member object(s).

CMD_LGTG writes Value / Priority pair(s) for a particular Group data tag to the Group command property of the Group manager object. The data is passed from the Group manager object to the Group member object(s) where it is distributed to the intended lighting output objects with matching Group data tag.

Compatible data points:

Analog lighting output [LgtAOut]
Binary lighting output [LtgBOut]

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

Required properties of grouped data points:

Present value
Control command (structured lighting output command)

Operate with priorities

The function block uses 2 approaches to control if operating with priorities:

1. Exclusive control (planned for priorities 1...5, 9...12, 14...16)

Initialized at startup

Multiple input sets of a function block cannot command the same priority.

2. Last win control (planned for priorities 7, 8, 13)

Not initialized at startup.

	Exclusive control Priorities: 1...5, 9...12, and 14...16	Last win control Priorities: 7, 8, and 13
Behavior at plant startup	[EnIn1] = 0 Release priority	[EnIn1] = 0 No release
Behavior at plant startup	[EnIn1] = 1 Command priority	[EnIn1] = 1 No command
Command process	If [EnIn1] changes from 0 to 1.	If [EnIn1] changes from 0 to 1.
	If [EnIn1] = 1 and [ValIn1] or [OpIn1] or [LvlIn1] or [StepIn1] change.	If [EnIn1] = 1 and [ValIn1] or [OpIn1] or [LvlIn1] or [StepIn1] change.
	If [EnIn1] = 1 and [RptcIn1] = 1.	If [EnIn1] = 1 and [RptcIn1] = 1.
Release	If [EnIn1] changes from 1 to 0.	If [EnIn1] changes from 1 to 0.
Release	If [EnIn1] = 0 and [RptcIn1] = 1.	If [EnIn1] = 0 and [RptcIn1] = 1.
Behavior in the event of commanding from another source	[EnIn1] = 0 Priority is not released by the function block.	[EnIn1] = 0 Priority is not released by the function block.
Behavior in the event of commanding from another source	[EnIn1] = 1 Priority is not commanded by the function block.	[EnIn1] = 1 Priority is not commanded by the function block.

The data point periodically saves the value of priority 8 to controller memory. After a power outage, the value is restored in the property 'Priority array' and evaluated by the data point. All other priorities are not saved to controller memory.

Operation with other input sets of function block ([EnIn2]...[EnIn4], [ValIn2]...[ValIn4], [OpIn2]...[OpIn4], [LvlIn2]...[LvlIn4], [StepIn1]...[StepIn4], [RptcIn2]...[RptcIn4]) is the same.

Pin description (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.

GrpTag1
Group data tag 1 Double word (default value: 0) [GrpTag1] defines specific group data for centralized distribution by the XFB. [GrpTag1] is used only for target state commanding (present value, priority). The system provides predefined and also user definable tags. [GrpTag1] 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.

GrpTag1

Group data tag 1

Double word (default value: 0)

[GrpTag1] defines specific group data for centralized distribution by the XFB. [GrpTag1] is used only for target state commanding (present value, priority).

The system provides predefined and also user definable tags. [GrpTag1] 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.

GrpTag2
Group data tag 2 Double word (default value: 0) [GrpTag2] defines specific group data for centralized distribution by the XFB. [GrpTag2] is used only for control-command commanding (control-command, priority). The system provides predefined and also user definable tags. [GrpTag2] 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.

GrpTag2

Group data tag 2

Double word (default value: 0)

[GrpTag2] defines specific group data for centralized distribution by the XFB. [GrpTag2] is used only for control-command commanding (control-command, priority).

The system provides predefined and also user definable tags. [GrpTag2] 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.

TshVal
Threshold value Real (default value: 0.1) A parameterized value used to control the XFB write attempts. An attempt is only allowed if the value difference is equal or greater than [TshVal]. Exception: the change equals a limit value such as 0.0 or 100.0 ([TshVal] is ignored). Note [TshVal] must not be set to 0.0.

TshVal

Threshold value

Real (default value: 0.1)

A parameterized value used to control the XFB write attempts. An attempt is only allowed if the value difference is equal or greater than [TshVal].

Exception: the change equals a limit value such as 0.0 or 100.0 ([TshVal] is ignored).

Note
[TshVal] must not be set to 0.0.

EnIn1...4
Enable input 1 Boolean (default value: False) [EnIn1] controls whether [ValIn1] or [OpIn1] is commanded at the priority held by [PrioIn1] or if the priority is released. [EnIn1] belongs to one of four input sets, each containing [EnInX], [ValInX], [OpInX], [LvlInX], [StepInX], [PrioInX], [RptcInX], and [DscdcInX]. These input sets command the grouped lighting output objects at different priorities as needed. [EnIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime. [EnIn2]...[EnIn4] functionality is identical to [EnIn1].
1 (True)	The priority held by [PrioIn1] is commanded.
0 (False) default	The priority held by [PrioIn1] is released if it is not currently active by a different [EnInX] set to True.

EnIn1...4

Enable input 1

Boolean (default value: False)

[EnIn1] controls whether [ValIn1] or [OpIn1] is commanded at the priority held by [PrioIn1] or if the priority is released.

[EnIn1] belongs to one of four input sets, each containing [EnInX], [ValInX], [OpInX], [LvlInX], [StepInX], [PrioInX], [RptcInX], and [DscdcInX]. These input sets command the grouped lighting output objects at different priorities as needed.

[EnIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime.

[EnIn2]...[EnIn4] functionality is identical to [EnIn1].

1 (True)

The priority held by [PrioIn1] is commanded.

0 (False)
default

The priority held by [PrioIn1] is released if it is not currently active by a different [EnInX] set to True.

ValIn1...4
Value input 1 Real (default value: 0.0) [ValIn1] is used to command the present value property at [PrioIn1] (target state commanding). [ValIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime. [ValIn1] will command present value at the priority held by [PrioIn1] if: [EnIn1] is True and [ValIn1] changes by a value equal or greater than [TshVal]. [EnIn1] is True and [ValIn1] changes by a limit value such as 0.0 or 100.0 ([TshVal] is ignored). [ValIn2]...[ValIn4] functionality is identical to [ValIn1]. Note If [ValIn1] is used, [OpIn1] must not be used and must remain at default value 32767.

ValIn1...4

Value input 1

Real (default value: 0.0)

[ValIn1] is used to command the present value property at [PrioIn1] (target state commanding).

[ValIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime.

[ValIn1] will command present value at the priority held by [PrioIn1] if:

[EnIn1] is True and [ValIn1] changes by a value equal or greater than [TshVal].
[EnIn1] is True and [ValIn1] changes by a limit value such as 0.0 or 100.0 ([TshVal] is ignored).

[ValIn2]...[ValIn4] functionality is identical to [ValIn1].

Note
If [ValIn1] is used, [OpIn1] must not be used and must remain at default value 32767.

OpIn1...4
Operation input 1 Integer (default value: 32767) [OpIn1] is used to command the control command property (sub elements [LvlIn1] and [StepIn1]) at [PrioIn1]. [OpIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime. If [OpIn1] equals the maximum integer value, the input set runs as a target state command. For all other values [OpIn1] runs as control-command. [OpIn1] will command at the priority held by [PrioIn1] if: [OpIn1] changes and [EnIn1] is True. [OpIn2]...[OpIn4] functionality is identical to [OpIn1]. Note If [OpIn1] is used, [ValIn1] must not be used.

OpIn1...4

Operation input 1

Integer (default value: 32767)

[OpIn1] is used to command the control command property (sub elements [LvlIn1] and [StepIn1]) at [PrioIn1].

[OpIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime. If [OpIn1] equals the maximum integer value, the input set runs as a target state command. For all other values [OpIn1] runs as control-command.

[OpIn1] will command at the priority held by [PrioIn1] if:

[OpIn1] changes and [EnIn1] is True.

[OpIn2]...[OpIn4] functionality is identical to [OpIn1].

Note
If [OpIn1] is used, [ValIn1] must not be used.

LvlIn1...4
Level input 1 Real (default value: 0.0) [LvlIn1] is part of the command field [OpIn1] and defines the target level for the input set. It is written to the lighting output object in conjunction with the commanding of [OpIn1] and is used in combination with some of the Op commands (for example, goto-level, fade-to, ramp-to). [LvlIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime. [LvlIn2]...[LvlIn4] functionality is identical to [LvlIn1].

LvlIn1...4

Level input 1

Real (default value: 0.0)

[LvlIn1] is part of the command field [OpIn1] and defines the target level for the input set. It is written to the lighting output object in conjunction with the commanding of [OpIn1] and is used in combination with some of the Op commands (for example, goto-level, fade-to, ramp-to).

[LvlIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime.

[LvlIn2]...[LvlIn4] functionality is identical to [LvlIn1].

StepIn1...4
Step input 1 Real (default value: 0.0) [StepIn1] is part of the command field [OpIn1] and defines the step increment for the input set. It is written to the lighting output object in conjunction with the commanding of [OpIn1] and is used in combination with some of the Op commands (for example, step-up and step-down). [StepIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime. [StepIn2]...[StepIn4] functionality is identical to [StepIn1].

StepIn1...4

Step input 1

Real (default value: 0.0)

[StepIn1] is part of the command field [OpIn1] and defines the step increment for the input set. It is written to the lighting output object in conjunction with the commanding of [OpIn1] and is used in combination with some of the Op commands (for example, step-up and step-down).

[StepIn1] can be parameterized (set by developer), or it is linkable in the CFC chart and calculated by the control program during runtime.

[StepIn2]...[StepIn4] functionality is identical to [StepIn1].

PrioIn1...4
Priority input 1 Integer (default value: 17) [PrioIn1] holds the priority that accompanies [ValIn1] or [OpIn1]. [PrioIn1] is parameterized and cannot be changed during runtime. A value of 17 means the input set is not being used. [PrioIn2]...[PrioIn4] functionality is identical to [PrioIn1]. Note Input sets on the same function block must not share a common exclusive control priority.
Priority range	1...16 See restrictions on priority 6 and priority 8 below.
Exclusive control	Priorities 1...5, 9...12 and 14...16 On start-up of the control program, the function block uses exclusive control to initialize any assigned priorities in ranges 1...5, 9...12 and 14...16. At runtime this function block does not support exclusive priority control. The last valid command or release controls the priority. Due to exclusive control during start-up, two or more input sets on the same function block must not share a common exclusive control priority, otherwise a conflict will result.
Last wins	Priorities 7, 8 and 13 No initialization of priorities on start-up. At runtime, last valid command (or release) controls the priority. If two or more input sets have the same priority and are commanded at the same time, only the input set in first numerical order is performed (In1...In4). Exception: If two or more input sets have the same priority, and inputs providing value (either target state or control-command) are changed at the same time, the input set in last numerical order will win (In1...In4). If two or more input sets have the same priority and conditions for commanding and releasing are given at the same time, the command operation wins.
Priority 6	Per BACnet, command priority 6 is reserved for minimum on/off functionality. Commands at priority 6 are rejected by the BACnet object. To provide minimum on/off functionality, the control program should contain the feature and command at another priority.
Priority 8	Per BACnet, command priority 8 is for manual operator use and is not typically assigned on the function block. Last wins functionality could allow the control program to change or release an operator command.

RptcIn1...4
Repeat command input 1 Boolean (default value: False) [RptcIn1] is used to force repeat a command or release a priority. If [RptcIn1] = 1 (True) and [EnIn1] = 1 (True), the function block forces a command of [ValIn1] or respectively [OpIn1], [LvlIn1] and [StepIn1] with every program cycle at the priority in [PrioIn1]. If [RptcIn1] = 1 (True) and [EnIn1] = 0 (False), the function block forces a release with every program cycle at the priority in [PrioIn1]. [RptcIn2]...[RptcIn4] functionality is identical to [RptcIn1]. Note [RptcIn1] must not be forced permanently to True by connecting to a block output that is always True. Doing so causes a high level of communication traffic. [RptcIn1] is linkable and will typically be calculated and set by the control program.

RptcIn1...4

Repeat command input 1

Boolean (default value: False)

[RptcIn1] is used to force repeat a command or release a priority.

If [RptcIn1] = 1 (True) and [EnIn1] = 1 (True), the function block forces a command of [ValIn1] or respectively [OpIn1], [LvlIn1] and [StepIn1] with every program cycle at the priority in [PrioIn1].
If [RptcIn1] = 1 (True) and [EnIn1] = 0 (False), the function block forces a release with every program cycle at the priority in [PrioIn1].

[RptcIn2]...[RptcIn4] functionality is identical to [RptcIn1].

Note
[RptcIn1] must not be forced permanently to True by connecting to a block output that is always True. Doing so causes a high level of communication traffic.

[RptcIn1] is linkable and will typically be calculated and set by the control program.

DscdcIn1...4
Discard command input 1 Boolean (default value: False) [DscdcIn1] is used to configure [ValIn1] command repeating in case of restart or to re-establish communication with group member’s automation station. [DscdcIn1] is parameterized and cannot be changed during runtime. If [DscdcIn1] = 0 (False) group manager will repeat the last command of [ValIn1] at priority [PrioIn1] in case of restart or to re-establish communication with group member’s automation station. If [DscdcIn1] = 1 (True) group manager will not repeat the last command of [ValIn1] at priority [PrioIn1] in case of restart or to re-establish communication with group member’s automation station. [DscdcIn2]...[DscdcIn4] functionality is identical to [DscdcIn1].

DscdcIn1...4

Discard command input 1

Boolean (default value: False)

[DscdcIn1] is used to configure [ValIn1] command repeating in case of restart or to re-establish communication with group member’s automation station.

[DscdcIn1] is parameterized and cannot be changed during runtime.

If [DscdcIn1] = 0 (False) group manager will repeat the last command of [ValIn1] at priority [PrioIn1] in case of restart or to re-establish communication with group member’s automation station.
If [DscdcIn1] = 1 (True) group manager will not repeat the last command of [ValIn1] at priority [PrioIn1] in case of restart or to re-establish communication with group member’s automation station.

[DscdcIn2]...[DscdcIn4] functionality is identical to [DscdcIn1].

Pin description (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.

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.

Use case examples

NOTICE

Note
Graphics reflect examples of XFB implementations; See ABT for current examples of CFC.

CMD_LGTG: Example taken from the Central lighting function AFN and CHT{CenOpLgt01}. Due to graphical size limitations, function blocks may be missing or shown more closely grouped than is typical.