OptStartHeat

OptStartHeat (FB)

FUNCTION_BLOCK OptStartHeat

Short description

Start-optimization for heating operation with an internal weekly timer (principle: variable preheat time) Objective: Room temperature = setpoint temperature at the start of daytime operation Typical application: zone control loop with heating valve

Representation

Interfaces

Inputs

Name	Data type	Value range	Initial value	Function
xEn	BOOL		FALSE	General enable of the switch-on optimization
xEnAdapt	BOOL		TRUE	Enable for storing data in the historical memory
xResAdapt	BOOL		TRUE	Reset of the historical memory
rTo	REAL			Current outdoor temperature
rTi	REAL			Current room temperature
rSetTemp	REAL			Current room setpoint temperature in comfort/daytime operation

Outputs

Name	Data type	Value range	Initial value	Function
xDaytime	BOOL		FALSE	Enable for comfort/daytime operation (Off = FALSE, On = TRUE)
xProcess	BOOL		FALSE	Enable - preheating process (Off = FALSE, On = TRUE)
bState	BYTE		0	Phase of the preheating process (0=Off/Deactivated, 1 = Check time, 2 = Dead time, 3 = Heating time, 4 = End of heating time)
wError	WORD		0	Error status of the last preheating process
bResult	BYTE		0	Quality of the last preheating process (0 = invalid, 1 = good, 2 = normal, 3 = poor)
xActive	BOOL		FALSE	State of the timer channel of the weekly clock (Off = FALSE, On = TRUE)
uiDeadTime	UINT		0	Display of the current dead time duration (min)
uiHeatTime	UINT		0	Display of the current heating time duration (min)
uiNumber	UINT		0	Display of the total number of successful preheating processes
rAverageDiff	REAL		0.0	Average absolute room temperature deviation of the last 10 successful preheating processes

Setpoints / parameters

Name	Data type	Value range	Initial value	Function
uiHGMin	UINT		30	Minimum value - heating gradient (min/K)
uiHGMax	UINT		240	Maximum value - heating gradient (min/K)
uiDTMin	UINT		10	Minimum value - dead time (min)
uiDTMax	UINT		180	Maximum value - dead time (min)
uiHTMin	UINT		15	Minimum value - heating time (min)
uiHTMax	UINT		600	Maximum value - heating time (min)
todMonFrom	TOD		TOD#07:00	Switch-on time - Monday
todMonTo	TOD		TOD#12:00	Switch-off time - Monday
xMonMode	BOOL		TRUE	Mode - switching period - Monday
todTueFrom	TOD		TOD#07:00	Switch-on time - Tuesday
todTueTo	TOD		TOD#12:00	Switch-off time - Tuesday
xTueMode	BOOL		TRUE	Mode - switching period - Tuesday
todWedFrom	TOD		TOD#07:00	Switch-on time - Wednesday
todWedTo	TOD		TOD#12:00	Switch-off time - Wednesday
xWedMode	BOOL		TRUE	Mode - switching period - Wednesday
todThuFrom	TOD		TOD#07:00	Switch-on time - Thursday
todThuTo	TOD		TOD#12:00	Switch-off time - Thursday
xThuMode	BOOL		TRUE	Mode - switching period - Thursday
todFriFrom	TOD		TOD#07:00	Switch-on time - Friday
todFriTo	TOD		TOD#12:00	Switch-off time - Friday
xFriMode	BOOL		TRUE	Mode - switching period - Friday
todSatFrom	TOD		TOD#07:00	Switch-on time - Saturday
todSatTo	TOD		TOD#12:00	Switch-off time - Saturday
xSatMode	BOOL		TRUE	Mode - switching period - Saturday
todSunFrom	TOD		TOD#07:00	Switch-on time - Sunday
todSunTo	TOD		TOD#12:00	Switch-off time - Sunday
xSunMode	BOOL		TRUE	Mode - switching period - Sunday
sNotice	STRING		'Own note - click to change.'	Label - timer

Global variables

Name	Data type	Value range	Initial value	Function
gc_Parameters.rTOMin	REAL		-25	Minimum value - outdoor temperature (°C)
gc_Parameters.rTOMax	REAL		25	Maximum value - outdoor temperature (°C)
gc_Parameters.rTIMin	REAL		15	Minimum value - room temperature (°C)
gc_Parameters.rTIMax	REAL		30	Maximum value - room temperature (°C)
gc_Parameters.rDiffSetTemp	REAL		0	Deviation from the room setpoint temperature at the end of the preheating process (K)
gc_Parameters.rDTDiffTemp	REAL		0.2	Increase of room temperature to detect the end of the dead time (K)
gc_Parameters.uiPHMaxTime	UINT		720	Maximum duration of the preheating process
gc_Parameters.rLimitResultWell	REAL		0.5	Result display: room temperature deviation - limit value for a good preheating process
gc_Parameters.rLimitResultNormal	REAL		1	Result display: room temperature deviation - limit value for a normal preheating process

Function description

The output *xDaytime* is, when start-optimization is generally enabled (*xEn* = TRUE), activated before the planned start of comfort/daytime operation depending on historical data, the current outside temperature, the current room temperature and the current setpoint temperature for the day/comfort operation. This preheating ensures that the room temperature already matches the desired setpoint at the start of daytime operation. The required preheat time is recalculated individually for each preheating process, and the actual preheat time is additionally incorporated into the historical data. Preheating processes spanning multiple days are possible. The start-optimization serves energy savings and increased user comfort. The components relevant for start-optimization are processed every 60 s. The preheating process is divided into four time segments. They are passed through sequentially during each successful preheating process. The preheating process can end before, exactly at, or after the switch-on point (= transition to comfort/daytime operation). \

Check time (bState = 1)

The check time is used for cyclic checking (every 60s) whether the conditions for enabling preheating are met. It begins if the following conditions are met simultaneously: \

1. The preheating process is not active ( xProcess = FALSE )\

2) The weekly clock is not active (*xActive* = FALSE) 3) There exists a valid next switch-on point It ends normally if the conditions for releasing the preheating are met (= start of dead time). It ends in any case if the next valid switch-on point equals the current time.\

Dead time (bState = 2)

The dead time is used for preconditioning the heating. It begins with the proper end of the check time. It ends properly if the current room temperature rTi exceeds the room temperature at the start of the dead time by the adjustable difference gc_Parameters.rDTDiffTemp permanently for a duration of at least 120s (= start of heating time). It ends in any case if the next valid switch-on point is equal to the current time. \

Heating time (bState = 3)

The heating time is used to preheat the zone. It begins with the proper end of the dead time. It ends properly if the current room temperature rTI the current room setpoint temperature in comfort/daytime operation rSetTemp permanently for a duration of at least 120s approaches to within a difference smaller than the global variable gc_Parameters.rDiffSetTemp approaches. It ends if a falling signal edge occurs on the state of the timer channel of the weekly clock xActive It ends if the current heating time duration exceeds the adjustable maximum value uiHTMax \

End of heating time (bState = 4)

The end of heating time serves to complete the successful preheating process. The historical data is updated, provided no limit values are violated, if the enable for storing data in the historical memory ( xEnAdapt ) is active. It begins with the proper end of the heating time. \

Enable xEn

This input serves for the general enable of the switch-on optimization ( xEn = TRUE). In the locked state ( xEn = FALSE) the outputs are defined as follows:\

Output	State/Value	Notes
xDaytime	FALSE
xProcess	FALSE
bState	0
wError	0
bResult	0
uiDeadTime	0
uiHeatTime	0
uiNumber	0
rAverageDiff	0

The historical data is retained even in the locked state. This input can also be used to activate sensor faults (fault - room temperature sensor, fault outdoor temperature sensor) or for operating the zone in extended occupancy time. \

Enable xEnAdapt

This input serves to enable storing data in the historical memory ( xEnAdapt = TRUE, prerequisite: xEn = TRUE). After each successful preheating process, the relevant parameters are stored and are thus available again for the next preheating process. In the locked state ( xEnAdapt = FALSE) no data is stored. \

Enable xResAdapt

This input serves to initialize the historical memory on each rising signal edge (prerequisite: xEn = TRUE ).\

Memory	State/Value	Notes
Heating gradients	uiHGMax
Dead times	uiDTMax
Number of preheating processes	0

In addition, the buffer for the average absolute room temperature deviation of the last 10 successful preheating processes and the data store for the current data are reset. \

Meaningful use of the input xResAdapt

This input can be used in combination with the output rAverageDiff (Average absolute room temperature deviation of the last 10 successful preheating processes) to trigger re-initialization of the historical and current data in the event of larger deviations.\

Input rTo

This input is used to acquire the current outdoor temperature. For switch-on optimization it is additionally time-filtered and limited (Minimum value = gc_Parameters.rTOMin, Maximum value = gc_Parameters.rTOMax ). \

Input rTi

This input is used to acquire the current room temperature. For switch-on optimization it is additionally time-filtered and limited (Minimum value = gc_Parameters.rTIMin, Maximum value = gc_Parameters.rTIMax ). \

Input rSetTemp

This input is used to acquire the current room setpoint temperature for comfort/daytime operation. Every change of the setpoint temperature triggers a reset to the base state (see Enable xEn - locked state). \

Output xDaytime

This output is used to enable comfort/daytime operation (Off = FALSE, On = TRUE) by the switch-on optimization. It is activated when transitioning from the check time to the dead time. It is deactivated when the next valid switch-on point is reached. \

Output xProcess

This output is used to indicate the active preheating process (Off = FALSE, On = TRUE). It is active if the preheating process is in phases 1 - 4 and/or the output xDaytime is active. \

Output bState

This output is used to indicate the active phase of the preheating process.\

Value	Phase
0	Off / Deactivated
1	Check time active
2	Dead time active
3	Heating time active
4	End of heating time active

Output wError

This output is used to indicate warnings/errors during the last preheating process. Each message is assigned a bit (Bit = 0 = no error, Bit = 1 = warning/error active). This output is updated continuously. On each change, the date/current time is also recorded. This output is always initialized to 0 (= no error) at the start of the check time. Whenever an error occurs, the preheating process is stopped and the ‘Off / Deactivated’ phase is initiated. Whenever a warning occurs, the output wError is updated.\

Bit	Cause	Error type	Notes
1	Exceeding the maximum heating time	Error
4	Limit violation heating gradient	Warning
5	Limit violation dead time	Warning
6	Falling below the minimum heating time	Warning

Output bResult

This output is used to indicate the quality of the last successful preheating process. The output is updated at the switch-on point (= transition to comfort/daytime operation) if necessary. The absolute value from the calculation of rSetTemp - gc_Parameters.rDiffSetTemp - rTi is used for the evaluation. This output is always initialized to 0 (= no result) at the start of the check time.\

Result	Limit value	bResult	Notes
less than	gc_Parameters.rLimitResultWell	1	Good preheating process
less than	gc_Parameters.rLimitResultNormal	2	Normal preheating process
greater than or equal	gc_Parameters.rLimitResultNormal	3	Poor preheating process

Output xActive

This output is used to display the state of the timer channel of the weekly clock (Off = FALSE, On = TRUE). The weekly clock is continuously updated regardless of the state of xEn (= general release of the start-optimization). When the settings of the weekly clock are changed, a reset to the default state occurs (see release xEn - locked state). \

Output uiDeadTime

This output is used to indicate the current dead time duration (min). This output is always initialized to 0 min at the start of the check time. \

Output uiHeatTime

This output is used to indicate the current heating time duration (min). This output is always initialized to 0 min at the start of the check time. \

Output uiNumber

This output is used to indicate the total number of successful preheating processes. \

Output rAverageDiff

This output is used to indicate the average absolute room temperature deviation of the last 10 successful preheating processes. This output is always updated after the output bResult is updated. This output is initialized to 0 K at each rising signal edge at the input xResAdapt . \

Meaningful use of the output rAverageDiff

This output can be used in combination with the input xResAdapt (Reset of the historical memory) to trigger re-initialization of the historical and current data in the event of larger deviations.\

1st preheating process

After the software download or after each rising signal edge at the input xResAdapt the historical data is re-initialized. The dead times are then written with the parameter uiDTMax, the heating gradients with the parameter uiHGMax and the number of successful preheating processes with the value 0. \

Parameter uiHGMin

This parameter is used to define the minimum permissible heating gradient (min/K). It is used to check for limit violations. In the event of a limit violation, the historical data is not updated. \

Parameter uiHGMax

This parameter is used to define the maximum permissible heating gradient (min/K). It is used to check for limit violations. In the event of a limit violation, the historical data is not updated. \

Parameter uiDTMin

This parameter is used to define the minimum permissible dead time (min). It is used to check for limit violations. In the event of a limit violation, the historical data is not updated. \

Parameter uiDTMax

This parameter is used to define the maximum permissible dead time (min). It is used to check for limit violations. In the event of a limit violation, the historical data is not updated. \

Parameter uiHTMin

This parameter is used to define the minimum permissible heating time (min). It is used to check for limit violations. \

Parameter uiHTMax

This parameter is used to define the maximum permissible heating time (min). It is used to check for limit violations. Whenever a limit violation occurs, the preheating process is stopped and the ‘Off / Deactivated’ phase is initiated. \

Parameter todMonFrom - sNotice

This parameter is used to configure the weekly clock. The general operation is described in detail in the documentation of the function block 'Clock7d1Ch'. \

Clock7d1Ch

Global variable gc_Parameters.rTOMin

This global variable is used to define the minimum permissible outdoor temperature (°C). It is used for checking and correcting limit violations. \

Global variable gc_Parameters.rTOMax

This global variable is used to define the maximum permissible outdoor temperature (°C). It is used for checking and correcting limit violations. \

Global variable gc_Parameters.rTIMin

This global variable is used to define the minimum permissible room temperature (°C). It is used for checking and correcting limit violations. \

Global variable gc_Parameters.rTIMax

This global variable is used to define the maximum permissible room temperature (°C). It is used for checking and correcting limit violations. \

Global variable gc_Parameters.rDiffSetTemp

This global variable is used to define the deviation from the room setpoint temperature at the end of the preheating process (K). It specifies how close the room temperature must approach the setpoint temperature in daytime/comfort operation to end the active preheating process. \

Global variable gc_Parameters.rDTDiffTemp

This global variable is used to define the increase in room temperature to detect the end of the dead time (K). It specifies how much the room temperature must increase permanently during the dead time to initiate the heating time. \

Global variable gc_Parameters.uiPHMaxTime

This global variable is used to define the maximum duration of the preheating process. It is used for internal calculations. \

Global variable gc_Parameters.rLimitResultWell

This global variable is used to define the limit value ‘Good preheating process’ for the quality display bResult. \

Global variable gc_Parameters.rLimitResultNormal

This global variable is used to define the limit value ‘Normal preheating process’ for the quality display bResult. \

Typical application

This function block can be applied as follows:

CODESYS

InOut:

Scope	Name	Type	Initial
Input	xEn	BOOL	FALSE
Input	xEnAdapt	BOOL	TRUE
Input	xResAdapt	BOOL	FALSE
Input	rTo	REAL
Input	rTi	REAL
Input	rSetTemp	REAL
Output	xDaytime	BOOL	FALSE
Output	xProcess	BOOL	FALSE
Output	bState	BYTE	0
Output	wError	WORD	0
Output	bResult	BYTE	0
Output	xActive	BOOL	FALSE
Output	uiDeadTime	UINT	0
Output	uiHeatTime	UINT	0
Output	uiNumber	UINT	0
Output	rAverageDiff	REAL	0.0
Input Const	uiHGMin	UINT	30
Input Const	uiHGMax	UINT	240
Input Const	uiDTMin	UINT	10
Input Const	uiDTMax	UINT	180
Input Const	uiHTMin	UINT	15
Input Const	uiHTMax	UINT	600
Input Const	todMonFrom	TOD	TIME_OF_DAY#7:0
Input Const	todMonTo	TOD	TIME_OF_DAY#18:0
Input Const	xMonMode	BOOL	TRUE
Input Const	todTueFrom	TOD	TIME_OF_DAY#7:0
Input Const	todTueTo	TOD	TIME_OF_DAY#18:0
Input Const	xTueMode	BOOL	TRUE
Input Const	todWedFrom	TOD	TIME_OF_DAY#7:0
Input Const	todWedTo	TOD	TIME_OF_DAY#18:0
Input Const	xWedMode	BOOL	TRUE
Input Const	todThuFrom	TOD	TIME_OF_DAY#7:0
Input Const	todThuTo	TOD	TIME_OF_DAY#18:0
Input Const	xThuMode	BOOL	TRUE
Input Const	todFriFrom	TOD	TIME_OF_DAY#7:0
Input Const	todFriTo	TOD	TIME_OF_DAY#18:0
Input Const	xFriMode	BOOL	TRUE
Input Const	todSatFrom	TOD	TIME_OF_DAY#7:0
Input Const	todSatTo	TOD	TIME_OF_DAY#18:0
Input Const	xSatMode	BOOL	TRUE
Input Const	todSunFrom	TOD	TIME_OF_DAY#7:0
Input Const	todSunTo	TOD	TIME_OF_DAY#18:0
Input Const	xSunMode	BOOL	TRUE
Input Const	sNotice	STRING	‘Notice’