Universal control function (UCtlFnct11 / UCtlFnct12)

Overview

The application function "Universal control function, PID controller, binary output (BO), analog output (AO)" (UCtlFnct11/12) is a generic function designed for flexible customization. It can be configured to handle miscellaneous automation tasks.

UCtlFnct11 and UCtlFnct12 are identical in function. Each can be configured / customized to handle a unique automation task.

Main features:

Loop object with multiple control input
Configurable evaluation parameters for the control input
Automatic enable/disable function with priority 15
Protection enable/disable function with priority 5
Triac control for auxiliary output functions
AO and/or BO command output(s)
Configurable switch-on, switch-off points for converting loop output to binary signal
Configurable delay options

Function

Inputs and outputs derive from the optional assignment of BACnet objects to collection objects. Each I/O arrangement depends on a customized configuration of the universal control function.

Inputs:

Control input: XctrCol (Collection of input to the PID controller).
Binary input: AutoDetCol (Collection of automatic detector). Automatic control priority 15.
Binary input: PrtDetCol (Collection of equipment protection detector). Priority 5.
Binary input: LgtBtnCol (Activate a triac for auxiliary output functions, not for lighting control). Priority 13.

Outputs:

Control Output: YctrCol (Collection of controller output).
Binary Output: SwiCmdCol (Collection of switch command).

Process value objects:

EnFnct (BPrcVal)
Sp (APrcVal)

The value of Enable function (EnFnct) enables/disables the binary output. The various inputs enable/disable EnFnct at priority 15 (auto detect), priority 13 (LgtBtnCol), or priority 5 (protection detect) respectively. See figure.

EnFnct is also used to enable/disable the control loop. When enabled, the control loop modulates controller output (YctrCol) to maintain controller input (XctrCol) at setpoint. The setpoint for the control loop is a process value object that can be set by commands from another device.

Legend
The legend describes general functionality. See Configuration for additional details.

1	PrtDetRs	BACnet object that represents the calculated result of binary input(s) used for equipment protection (Prio 5). Spare binary inputs BI(*) can be assigned to the collection object (PrtDetCol). In CET applications, the Room alarm object (RAlm, Alarm from room) can also be assigned.
2	AutoDetRs	BACnet object that represents the calculated result of binary input(s) used for auto detect (Prio 15). Window contacts (WndCont), presence detectors (PscDet) and spare binary inputs BI(*) can be assigned to the collection object (AutoDetCol). In CET applications, the Room alarm object (RAlm, Alarm from room) can also be assigned.
3	LgtBtnCol	Allows a PL-Link wall switch to be used to control a triac for auxiliary output functions. Since universal control function runs at lower priority within the DXR, do not use this triac output feature for functions requiring guaranteed response time below 300ms (e.g. Room lighting and shading control; response time can be approximately one second depending on internal processes at runtime.)
4	XctrRs	BACnet object that represents the calculated result of analog input(s) used in the universal control function. Supported inputs (includes KNX PL-Link): TR() – Room temperature HuRelR() – Room relative humidity AQualR() – Room air quality AI() – Spare analog inputs
5	EnFnct	BACnet object that uses the evaluated result of binary input(s) to enable/disable a control function.
6	DlySwiCmd	Configurable delay parameter, default 60 seconds.
7	DlyEnCtr	Configurable delay parameter, default 60 seconds.
8	Sp	Configurable setpoint for the loop object.
9	Ctr	The loop object.
10	SrcSelSwiCmd	The source selection parameter that selects either EnFnct signal or PID controller signal to send to the SwiCmdCol (switch command collection) object.
11	SwiOnPt SwiOffPt	The PID controller signal is converted from analog to binary value using configurable switch-on, switch-off points. (default 66% switch-on, 33% switch-off)
12	SwiCmdCol	The binary output value. Only spare binary output(s) BO(*) can be assigned to the collection object.
13	YctrCol	The analog output value. Only spare analog output(s) AO(*) can be assigned to the collection object.

TR, HuRelR, and AQualR Inputs Are Always Part of Room Calculation

These inputs, when used in the universal control function, are always linked with the room calculation. See graphic.
(TR inputs shown but also applies to HuRelR and AQualR)

Example use cases

Example 1: Damper end switch triggers the EnFnct to No/Yes. EnFnct activates the BO that enables the fan. After a 30 second time delay, PID loop will be enabled and will start controlling fan speed to maintain a pressure setpoint. (Delay time is configurable, default is 60 seconds.)

Example 2: Turning on/off the PID loop based on time schedule to control the bathroom temperature with a radiator.

Configuration

Parameters

Description	Parameter	Default value
Delay for switching command ▶ Time delay for SwiCmdCol output, when source selection (SrcSelSwiCmd) is set to 0:Control mode.	DlySwiCmd	60 [s]
Delay for enable controller ▶ Time delay for enabling/disabling the loop object.	DlyEnCtr	60 [s]
Source selection for switching command ▶ The source selection for either EnFnct signal or controller signal. 0:Enable function 1:Controller	SrcSelSwiCmd	1:Controller
Controller action ▶ The setting for loop action output. 0:Direct 1:Reverse	CtrActg	0:Direct
Controller input evaluation ▶ The setting for how analog input(s) are evaluated (affects item #3 in signal flow graphic above). 1:Sum 2:Average 3:Minimum 4:Maximum 5:Last updated	XctrEvl	2:Average
Automatic detector evaluation ▶ The setting for how binary input(s) are evaluated (affects item #2 in signal flow graphic above). 1:AND 2:OR 3:Last updated	AutoDetEvl	2:OR
Protection detector evaluation ▶ The setting for how protection binary input(s) are evaluated (affects item #1 in signal flow graphic above). Enumeration see Automatic detector evaluation	PrtDetEvl	2:OR
Protection mode configuration ▶ Parameter that defines the EnFnct value at protection priority. 0:Off 1:On	PrtModCnf	0:Off
Switch-on point ▶ Loop output must be at the configured value to convert analog signal to binary "On".	SwiOnPt	66 [%]
Switch-off point ▶ Converted analog signal will switch from On to Off when loop output falls to the configured value.	SwiOffPt	33 [%]

Interface

Interface		Description	Type	Ref.	Owned by
YctrCol		Collection of controller output	ColView	●	-
	YctrRs	Result of controller output	ACalcVal	●	-
XctrCol		Collection of controller input	ColView	●	-
	XctrRs	Result of controller input	ACalcVal	●	-
Sp		Setpoint	APrcVal	●	-
EnFnct		Enable function 0:No 1:Yes	BPrcVal	●	-
Ctr		Controller	Controller	●	-
SwiCmdCol		Collection of switching command	ColView	●	-
	SwiCmdRs	Result of switching command	BCalcVal	●	-
AutoDetCol		Collection of automatic detector	ColView	●	-
	AutoDetRs	Result of automatic detector 0:Off 1:On	BCalcVal	●	-
PrtDetCol		Collection of protection detector	ColView	●	-
	PrtDetRs	Result of protection detector 0:Off 1:On	BCalcVal	●	-
LgtBtnCol		Collection of lighting pushbutton	ColView	●	-
	LgtBtn	Lighting pushbutton 0:Off 1:On	LgtIn	●	-

Engineering and commissioning

Expert use (CFC programming):

UCtlFnct11/12 used as basic structure for custom programming.
Connect BACnet objects to the universal control function AF inputs to "add features" to the application (not just unrelated automation functions). The user re-addresses the input XFB(s) in the universal control function so they read temperatures, flows or other values from the application.
Drive BACnet objects in the existing application. To do this successfully, the user must pay attention to the priority of the pre-programmed commands and those added to the same objects.