ValveAnalog (FB)¶

FUNCTION_BLOCK ValveAnalog

Short Description¶

Control of a continuous valve drive with blocking protection function

Typical application: Control valve in a heating circuit

Portrayal¶

Interfaces¶

Inputs¶

Name
Datatype

Range

Init-Value

Function

rY REAL
Control signal off Regulation

rU REAL 0.0
Position feedback from the control valve

byAU BOOL
Feedback - Automatic operation

rPoti REAL
Feedback - Control signal from hardware manual level

Outputs¶

Name
Datatype

Range

Init-Value

Function

xHA REAL
Control signal after manual override

rAA REAL
Control signal before manual override

xAlarm BOOL
collective fault message

dtAbsLastOn DATE_AND_TIME
Date / time of the last blocking protection operation

sStatus STRING

Message texts for the operating status (1 = highest priority)

1:
‘Fault position monitoring’.

2:
‘Control via automatic control’

2:
‘Controlled by manual hardware’

3:
‘Control via manual software’

Setpoints / Parameters¶

Name
Datatype

Range

Init-Value

Function

udiControlTime UDINT 0 ... 600s 180s
Monitoring of the valve position: signal delay

rControlDiff REAL 7.0%
Monitoring of the valve position: Maximum position deviation

xControl BOOL TRUE
Monitoring of the valve position: enable / disable

rAbsMaxLimit REAL 100.0
Upper limit value for the control signal before manual override

rAbsMinLimit REAL 0.0
Lower limit value for the control signal before manual override

udiAbsTime UDINT 10s ... 600s 180s
Duration of blocking protection operation

tAbsStartTime TOD 00:00:00 - 23:59:59 Uhr 08:00:00 Uhr
Time point of blocking protection operation

eAbsDay eDoW eDoW.Monday ... eDoW.Sunday eDoW.Monday
Weekday of the blocking protection operation

rManValue REAL 0.0
Manual override: Hand value

eManModeN eMANNUM eMANNUM.Auto, eMANNUM.Man
Manual override: Operating mode

Functional description¶

rAA control signal before manual override¶

The rAA control signal before manual override is influenced by the blocking protection module. The blocking protection module is parameterised by the
udiAbsTime, tAbsStartTime und eAbsDay set-points/ parameters, the *rU*position feedback from the control valve being used as input signal.
The minimum change in valve position to lock the blockin protection function is fixed at 10.0%.
The rAA control signal before manual override is limited by ​​**rAbsMinLimit** and rAbsmaxLimit, the two absolute limit values.
The rU position feedback from the control valve can be replaced by the rY control signal from regulation if no position feedback is available.

rHA control signal after manual override¶

The rHA control signal after manual override is influenced by the output of the anti-lock module, the rY control signal from regulation and the manual override.

eManModeN
Blocking protection process
rHA
Notes

eMANNUM.Auto FALSE rY
Automatic operation with passive blocking protection process

eMANNUM.Auto TRUE
Output of the blocking protection process

Automatic operation with active blocking protection process

eMANNUM.Man X rManValue
manual override

Legend: X = any

position monitoring¶

The position monitoring can be enabled (**xControl**= TRUE) or disabled (**xControl**= FALSE).
When position monitoring is enabled, the value of the difference between the rHA control signal after manual override and the rU position feedback from the control valve is permanently determined
and compared to the **rControlDiff**limit value. If this difference permanently exceeds the limit value during a **udiControlTime**message delay, an alarm signal is generated if
at the same time the feedback - automatic operation *byAU*signals the automatic operation (*byAU*= 0). This alarm signal is displayed with the highest priority at the sStatus output in plain text
and at the same time the xAlarm collective fault message (*xAlarm*= TRUE) is transmitted. The alarm signal is deactivated again (*xAlarm*= FALSE) as soon as the difference
falls again below the limit value

rU position feedback from the control valve¶

The rU position feedback from the control valve can be replaced by the rY control signal from regulation if no position feedback is available.

blocking protection module¶

The blocking protection module is implemented by the numerical blocking protection module with adjustable time duration (FB: AbsA).
The udiAbsTime time period, the todAbsStartTime point in time and the eAbsDay weekday are adjustable.
The minimum run time for locking the blocking protection operation is 30s.
The dtAbsLastOn time stamp (date / time) of the last anti-lock operation is available.

Visualization¶

Information¶

Element
Authors

Date
Version
Note

Function
Alexander Halter 06.2016 1.0
Initial version

Programming
Alexander Halter 06.2016 1.0
Initial version

Test Jochen Reu 11.2017 1.0
Initial version

Documentation
Jochen Reu 11.2017 1.0
Initial version

Codesys¶

InOut:

Scope	Name	Type	Initial	Comment
Input	rY	REAL		Stellsignal z.B. vom PI-Regler
	rU	REAL	0	Feedback Valve position
	eAO	eManNum	HVACTYPES.eManNum.Auto	Manual - Switch position (A) Auto, (O)n
	rPoti	REAL		Poti position of the hardware manual level
Output	rHA	REAL		Control
	rAA	REAL		Control Regulation
	xAlarm	BOOL		Fault message via valve position
	dtAbsLastOn	DT		Last Start ABS function
	sStatus	STRING		Status Message
Input	udiControlTime	UDINT	180	Time in seconds from 10sec - 10min
	rControlDiff	REAL	7	Maximum permissible deviation between nominal and actual position in %.
	xControl	BOOL	TRUE	Enable Monitoring of the valve position
	rAbsMaxLimit	REAL	100	Upper limit value for the control signal
	rAbsMinLimit	REAL	0	Lower limit value for the control signal
	udiAbsTime	UDINT	180	ABS Time of the valve. Time in seconds from 0sec - 10min
	todAbsStartTime	TOD	TIME_OF_DAY#8:0	Time at which blocking protection is executed
	eAbsDay	eDoW	eDow.Monday	Weekday on which the blocking protection is executed
	rManValue	REAL	0	HandWert
	eManModeN	eMANNUM	eMANNUM.Auto	0=Automatic operation 1=Manual operation