BAC_AC_OpMod_01

Functional description

The template BAC_AC_OpMod_01 prioritizes different events or commands of an air-conditioning plant, such as fire alarm, request of central switching or schedule and writes a resulting operation mode or resulting system status to the variable udiOpMod.
The devices and aggregates respond individually, depending on udiOpMod, so that the whole plant adjusts itself according to the current operation mode.

Sample: 1
The mixed-air system BAC_AC_MixAT_01 switches to a fresh air rate of 100%, if udiOpMod is in summer night cooling mode (udiOpMod = 11).

Sample: 2
The supply air and extract air fan switches on if forced ventilation is enabled. Controlled fans crank up to a speed of 100%.

Interface

System diagram

Block diagram

The following system states or operation modes are described via the variable : udiOpMod

VAR_INPUT

bOn            : BOOL;
bFrst          : BOOL; 
bAlmShutOff    : BOOL; 
bNgtCol        : BOOL; 
bColDwnPrtc    : BOOL; 
bOvrHtgPrtc    : BOOL; 
bFireDetc      : BOOL;
bSmExttSuA     : BOOL;
bSmExttExuA    : BOOL;
bForcVent      : BOOL;
bEmgOff        : BOOL;
bCentSwiOff    : BOOL; 

bOn: Request from timer program

bFrst: Frost protection program active

bAlmShutOff: Collective fault message - shut down plant

bNgtCol: Request from summer night cooling program

bColDwnPrtc: Request from cooling protection program

bOvrHtgPrtc: Request from overheating protection program

bFireDetc: Fire alarm message from fire alarm center

bSmExttSuA: Additional flow requested by supply air section of the plant for smoke extraction.

bSmExttExhA: Smoke extraction with extract air section of the plant requested.

bForcVent: Forced ventilation request

bEmgOff: Emergency Stop

bCentSwiOff: Central shutdown

VAR_OUTPUT

udiOpMod      : UDINT;

udiOpMod: Output of the current plant operation mode.

VAR CONSTANT

PLT_NUM    : BYTE := 1;

PLT_NUM: all alarms and events of all plant components within a controller are included in a global alarm and event list. The assignment of events and alarms to a plant is defined by the assignment of a PLT_NUM plant number.
The recording and processing of an alarm from an aggregate or a device takes place within the templates by means of the alarm function block FB_BA_Alarm.
The evaluation of the alarms of a plant, e.g. for the generation of a collective message or for plant shutdown in case of relevant faults, takes place within the template BAC_PltAlm_01 by means of the function block FB_BA_AlarmPlt.
The evaluation of different plant events within the templates of a plant, takes place within the template BAC_PltComnMsg_01 by means of the function block FB_BA_ComnMsg.

Important! The assignment and evaluation of the alarms and events of a plant can only be done correctly if all templates of a plant have the same plant number!

The plant number can be assigned in the Project Builder in the parameter menu for the templates or via a column in the Excel import.

Program description

Version history