FB_BA_SunBldIcePrtc

The function block FB_BA_SunBldIcePrtc deals with direction-independent anti-icing.

Weather protection has the highest priority for blind control (see Overview) and should ensure that the blind is not damaged by ice.

Impending icing up is detected when the measured outside temperature fOtsT falls below the frost limit value fFrstT while at the same time rain is detected on bRainSns. This event is saved internally and remains active until it is ensured that the ice has melted again. In addition, the outside temperature must have exceeded the frost limit value for the entered deicing time nDeiceTi [s]. For safety reasons the icing event is persistently saved, i.e. also beyond a PLC failure. Thus, if the controller fails during the icing up or deicing period, the blind is considered to be newly iced up when then the controller restarts and the deicing timer starts from the beginning again.

If there is a risk of icing, the blind is moved to the protection position specified by fPosProt (height position [%]) and fAnglProt (lamella angle [°]).

Inputs

VAR_INPUT
  bEn              : BOOL;
  fOtsT            : REAL;
  bRainSns         : BOOL;
  fFrstT           : REAL;
  nDeiceTi         : UDINT;
  fPosProt         : REAL;
  fAnglProt        : REAL;
END_VAR

Name	Type	Description
bEn	BOOL	A TRUE signal on this input activates the function block and transfers the entered setpoints together with the active flag in the positioning telegram ST_BA_SunBld. A FALSE signal resets the active flag again and sets position and angle to zero. bActv is FALSE. This means that another function takes over control of the blind via the priority controller.
fOtsT	REAL	Outside temperature [°C]
bRainSns	BOOL	Input for a rain sensor.
fFrstT	REAL	Icing up temperature limit value [°] Celsius. This value may not be greater than 0. Otherwise an error is output.
nDeiceTi	UDINT	Time until the deicing of the blind after icing up [s]. After that the ice alarm is reset.
fPosProt	REAL	Height position of the blind [%] in the case of protection.
fAnglProt	REAL	Lamella angle of the blind [°] in the case of protection.

Inputs CONSTANT PERSISTENT

VAR_INPUT CONSTANT PERSISTENT
  ePrio    : E_BA_SunBldPrio := E_BA_SunBldPrio.eIce;
END_VAR

Name	Type	Description
ePrio	E_BA_SunBldPrio	Priority of the active telegram.

Outputs

VAR_OUTPUT
  stSunBld            : ST_BA_SunBld;
  bActv               : BOOL;
  bIceAlm             : BOOL;
  nRemTiIceAlm        : UDINT; 
END_VAR

Name	Type	Description
stSunBld	ST_BA_SunBld	Output structure of the blind positions.
bActv	BOOL	Corresponds to the boolean value bActv in the blind telegram ST_BA_SunBld and is solely used to indicate whether the function block sends an active telegram.
bIceAlm	BOOL	Indicates the icing up alarm.
nRemTiIceAlm	UDINT	In the case of impending icing up (bIceAlm = TRUE), this second counter is set to the deicing time. As soon as the temperature lies above the frost point entered (fFrstT), the remaining number of seconds until the 'all-clear' signal is given (bIceAlm = FALSE) is displayed here. This output is 0 as long as no countdown of the time is taking place.

	If an error occurs, this automatic control is disabled and the position and angle are set to 0. This means that if a priority controller is in use, another function with a lower priority (see Overview) automatically takes over control of the blind. In the case of a direct connection, conversely, the blind will drive to position/angle 0.

Requirements

Development environment	Required PLC library
TwinCAT from v3.1.4024.22	Tc3_BA2 from v5.2.5.0