BAC_AC_SeqH_01
Functional description
The template BAC_AC_SeqH_01 is responsible for starting the supply air sequence control for humidification and dehumidification of an air-conditioning plant.
On startup of the air-conditioning plant the system determines whether to start with the humidification sequence or the dehumidification sequence. The start sequence is selected depending on the plant steps and the absolute room humidity.
Only one element of the sequence can be in control. When the output of a controlling sequence element reaches Y Min or Y Max, the control is transferred to the next sequence controller that is ready for switch-on.
Interface
System diagram
Block diagram
Order of the sequences
The sequence of the sequence controllers of the individual aggregates must correspond to the sequence order.
The assignment of the sequence numbers does not have to be continuous, there may be free connections.
Example: 1 = humidifier, 4 = cooler/dehumidifier
Globally defined sequence numbers of the sequence controllers:
1 | Sequenznummer Befeuchter//Sequence number humidifier | |
2 | Sequenznummer Mischluft//Sequence number mixed air | |
3 | Sequenznummer Energierückgewinnung//Sequence number energy recovery | |
4 | Sequenznummer Entfeuchter//Sequence number dehumidifier | |
5 | kein Sequenzregler aktiv//no sequence controller active |
VAR_INPUT
udiPltStp : UDINT;
rRmX : REAL;
rSpHumf : REAL;
rSpDehumf : REAL;
udiPltStp: Steps during startup of the air-conditioning plant. See also BAC_AC_StartTH_01
rRmX: Measured value room humidity (absolute humidity)
rSpHumf: Set value humidification (absolute humidity)
rSpDehumf: Set value dehumidification (absolute humidity)
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!
Within a ventilation system with sequence controller the plant number indicates which field from the global data structure g_stSeqLinkH[PLT_NUM] is used as link between the individual sequence controllers and the corresponding control function blockFB_BA_SeqLink.
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
Instance | Type | Task |
|---|---|---|
SttSeqH | The priority switch is used to select the start sequence. | |
SeqLinkH | The function block SeqLinkH is the core of the template BAC_SeqH_01. The sequence linker is linked with all supply air controllers of the sequence via the global data structure g_stSeqLinkH[PLT_NUM]. The central control element is responsible for switching between the sequence controllers and starting the control sequence. | |
CurSeqH | The MV object indicates the currently active sequence controller. |
Version history
Version number | Comments |
|---|---|
1.0.1 | First release |