FB_BA_SunBldIcePrtc

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

The weather protection has the highest priority in the blind controller (see overview) and is intended to ensure that the blind is not damaged by ice or wind.

Impending icing up is detected by the fact that, during precipitation detection at bRainSns, the measured outside temperature rOtsT is below the frost limit rFrstT. 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 udiDeiceTi_sec [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 protective position specified by rPosProt (height position in percent) and rAnglProt (louvre angle [°]).

VAR_INPUT

bEn              : BOOL;
rOtsT            : REAL;
bRainSns         : BOOL;
rFrstT           : REAL;
udiDeiceTi_sec   : UDINT;
rPosProt         : REAL;
rAnglProt        : REAL;

bEn: The function block has no function if this input is FALSE. In the positioning telegram ST_BA_Sunbld 0 is output for the position and the angle, and bActv is FALSE. This means that another function takes over control of the blind via the priority controller.

rOtsT: Outside temperature [°C].

bRainSns: Input for a rain sensor.

rFrstT: Icing up temperature limit value [°] Celsius. This value may not be greater than 0. Otherwise an error is output.

udiDeiceTi_sec: Time until the deicing of the blind after icing up [s]. After that the icing up alarm is reset.

rPosProt: Height position of the blind [%] in the case of protection.

rAnglProt: Louvre angle of the blind [°] in the case of protection.

VAR_OUTPUT

stSunBld            : ST_BA_SunBld;
bActv               : BOOL;
bIceAlm             : BOOL;
udiRemTiIceAlm_sec  : UDINT;

stSunBld: Output structure of the blind positions, see ST_BA_SunBld.

bActv: 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: Indicates the icing up alarm.

udiRemTiIceAlm_sec: 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 (rFrstT), the remaining number of seconds until the 'all-clear' signal is given (bIceAlm=FALSE) are indicated here. This output is 0 as long as no countdown of the time is taking place.

If an error occurs, this automatic control is deactivated, 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