FB_BA_SunPrtc
The function block FB_BA_SunPrtc is used for glare protection with the aid of a slatted blind.
Glare protection is realized through variation of the slat angle and positioning of the blind height.
The slat angle is set as a function of the sun position such that direct glare is prevented, while letting as much natural light through as possible.
Three different operation modes are available for varying the blind height.
- When sun protection is active, the blind moves to a fixed height. The height value is specified with the variable fFixPos.
- The blind position is varied as a function of the position of the sun. The position is specified in the table (ST_BA_BldPosTab). See also description of FB_BA_BldPosEntry.
- The high of the blind is calculated based on the window geometry such that the sun's rays reach a specified depth in the room. The incidence depth of the sun's rays is defined with the variable fMaxLgtIndc.
In order to avoid excessive repositioning of the slat angle, the variable nPosIntval [min] can be used to specify a time interval, within which the slat angle is not adjusted. In order to avoid glare, the angle is always changed sufficiently for the respective time interval.
The following conditions must be met for positioning the blind and setting the slat angle.
- 1. The input bEn must be TRUE.
- 2. The sun must have risen. (elevation > 0)
- 3. The function block is parameterized correctly (bErr = False)
Inputs
VAR_INPUT
bEn : BOOL;
tUTC : TIMESTRUCT;
nPosIntval : UDINT;
fDegLngd : REAL;
fDegLatd : REAL;
fFcdOrtn : REAL;
fFcdAngl : REAL;
fLamWdth : REAL;
fLamDstc : REAL;
fFixPos : REAL;
fMaxLgtIndc : REAL;
fWdwHght : REAL;
fDstcWdwFlr : REAL;
stBldPosTab : ST_BA_BldPosTab;
ePosMod : E_BA_PosMod := E_BA_PosMod.eFix;
END_VAR
Name | Type | Description |
|---|---|---|
bEn | BOOL | If this input is set to FALSE, the positioning is inactive, i.e. the active bit (bActv) is reset in the positioning structure stSunBld of the type ST_BA_SunBld and the function block itself remains in a standstill mode. If on the other hand the function block is activated, then the active bit is TRUE and the function block outputs its control values (fPos, fAngl) in the positioning structure at the appropriate times. |
stUTC | TIMESTRUCT | Input of current time as UTC - Coordinated Universal Time (previously referred to as GMT, Greenwich Mean Time) (see TIMESTRUCT). The function block FB_BA_GetTime can be used to read this time from a target system. |
 | A jump of more than 300 seconds leads to immediate repositioning, if the blind is in the sun and glare protection is active, based on the above criteria. This functionality was added to ensure a reproducible program execution. |
Name | Type | Description |
|---|---|---|
nPosIntval | UDINT | Positioning interval in minutes - time between two blind position outputs. Valid range: 1 min...720 min. |
fDegLngd | REAL | Longitude [°]. Valid range: - 180°...180°. |
fDegLatd | REAL | Latitude [°]. Valid range: - 90°...90°. |
fFcdOrtn | REAL | Facade orientation [°]. |
In the northern hemisphere, the following applies for the facade orientation (looking out of the window):
Viewing direction | Facade orientation |
|---|---|
North | β=0° |
East | β=90° |
South | β=180° |
West | β=270° |
The following applies for the southern hemisphere:
Viewing direction | Facade orientation |
|---|---|
South | β=0° |
East | β=90° |
North | β=180° |
West | β=270° |
Name | Type | Description |
|---|---|---|
fFcdAngl | REAL | Facade inclination [°] (see Facade inclination). |
fLamWdth | REAL | Width of the slats in mm (see sketch). |
fLamDstc | REAL | Slat spacing in mm (see sketch). |
fFixPos | REAL | Fixed (constant) blind height [0...100%]. Applies if ePosMod = ePosModFix (see E_BA_PosMod). |
fMaxLgtIndc | REAL | Maximum desired light incidence in mm measured from the outside of the wall (see height adjustment). The parameters fWdwHght and fDstcWdwFlr are used to calculate how high the blinds must be, depending on the position of the sun, such that the incidence of light does not exceed the value fMaxLgtIndc. Applies if ePosMod = ePosModeMaxIncidence (see E_BA_PosMod). |
fWdwHght | REAL | Window height in mm for the calculation of the blind height if the mode "maximum desired incidence of light" is selected. |
fDstcWdwFlr | REAL | Distance between the floor and the window sill in mm for the calculation of the blind height if the mode "maximum desired incidence of light" is selected. |
stBldPosTab | ST_BA_BldPosTab | Table of 6 interpolation points, 4 of which are parameterizable, from which a blind position is then given in relation to the position of the sun by linear interpolation. Applies if ePosMod = ePosModFix (see E_BA_PosMod). For a more detailed description please refer to FB_BA_BldPosEntry. |
ePosMo | E_BA_PosMod | Selection of the positioning mode |
Inputs CONSTANT PERSISTENT
VAR_INPUT CONSTANT PERSISTENT
ePrio : E_BA_SunBldPrio := E_BA_SunBldPrio.eSunProtection;
fAnglLmtUp : REAL;
END_VAR
Name | Type | Description |
|---|---|---|
ePrio | E_BA_SunBldPrio | Priority of the active telegram. |
fAnglLmtUp | REAL | Slats do not need to be opened above 0°. |
Outputs
VAR_OUTPUT
stSunBld : ST_BA_SunBld;
bActv : BOOL;
bErr : BOOL;
sErrorDescr : T_MAXSTRING;
END_VAR
Name | Type | Description |
|---|---|---|
stSunBld | Output telegram, for the position and angle of the lamella. | |
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. |
bErr | BOOL | In case of a fault, e.g. if warning stages are active, this output is set to TRUE. |
sErrDescr | T_MAXSTRING | Contains the error description. |
Error description |
|---|
01: Error: The duration of the positioning interval is less than or equal to zero, or it exceeds 720 min. |
02: Error: The value entered for the longitude is not in the valid range of -180°...180°. |
03: Error: The value entered for the latitude is not in the valid range of -90°...90°. |
04: Error: The value entered for the facade inclination fFcdAngl is outside the valid range of -90°..90°. |
05: Error: The value for the slat spacing (fLamDstc) is greater than or equal to the value for the slat width (fLamWdth). This does not represent a "valid" blind, since the slats cannot close fully. Mathematically, this would lead to errors. |
06: Error: The value entered for the slat width fLamWdth is zero. |
07: Error: The value entered for the slat spacing fLamDstc is zero. |
08: Error: The value entered for the fixed blind height (fFixPos) is greater than 100 or less than 0. At the same time, positioning "fixed blind height" is selected - ePosMod = ePosModFix. |
09: Error: The "Values valid" bit (bVld) in the stBldPosTab positioning table is not set - invalid values, see FB_BA_BldPosEntry. At the same time, "Table" positioning is selected – ePosMod = ePosModTab. |
10: Error: The value entered for the maximum required light incidence fMaxLgtIndc is less than or equal to zero. At the same time, "maximum light incidence" is selected – ePosMod = ePosModMaxIndc. |
11: Error: The value entered for the window height fWdwHght is less than or equal to zero. At the same time, "maximum light incidence" is selected – ePosMod = ePosModMaxIndc. |
12: Error: The distance between lower window edge and floor fDstcWdwFlr that was entered is less than zero. At the same time, "maximum light incidence" is selected – ePosMod = ePosModMaxIndc. |
13: Error: An invalid positioning mode is entered at input ePosMod. |
| 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 |