# Burner2Stage ## `Burner2Stage` (FB) FUNCTION\_BLOCK Burner2Stage ### Short description > Control of a heat generator (temperature control via binary control commands More / Less)\ > \ > Typical application: heat generation ### Representation
### Function description #### General This function block is used to control / regulate a heat generator depending on the demand of the heat generator *xEn*, the supply setpoint temperature *rSetPtTemp* and the supply temperature *rFdT*.\ The enable / disable of the heat generator is done via the output *xHB* (FALSE = lockout, TRUE = enable).\ The flow temperature control (analogously also boiler temperature control) is carried out by means of two power controllers (P-controllers, slow and fast) via the outputs *xMoreHB* and *xLessHB*.\ The enabling of the control is delayed (setpoint / parameter **udiWaitControl**) after the running feedback (*xFb* = TRUE) of the heat generator.\ \ The following function blocks are essentially used: ControlP Out3P OperatingHours ManBin #### Enable / disable of the heat generator The enabling of the heat generator (*xAB* = TRUE, *xHB* = TRUE (eManModeB = eManBin.Auto)) occurs if the supply temperature *rFdT* the sum of supply setpoint temperature *rSetPtTemp* and setpoint / parameter **rSwitchOnPoint** falls below, at the same time the general enable *xEn* active (= TRUE) and the minimum off-time is not active.\ The disabling of the heat generator (*xAB* = FALSE, *xHB* = FALSE (eManModeB = eManBin.Auto)) occurs if the supply temperature *rFdT* the sum of supply setpoint temperature *rSetPtTemp* and setpoint / parameter **rSwitchOffPoint** exceeds and at the same time the general enable *xEn* is active (= TRUE).\ Between two consecutive operating cycles a minimum off-time is always inserted (duration = **udiTimeMinOff**, display - remaining time: *tOnDelay*).\ The minimum off-time begins with the falling edge (TRUE > FALSE) at the input *xFb*. #### Temperature control of the heat generator The enabling of the temperature control is delayed (duration = **udiWaitControl**, display - remaining time: *tOnControlDelay*)\ after the active running signal (*xFb* = TRUE) of the heat generator.\ The disabling of the temperature control occurs immediately after the inactive running signal (*xFb* = FALSE) of the heat generator (switch-off value: **rYDisabled**).\ The two internal power controllers (P-controllers, slow and fast, output range each -100.0 - 100.0 %) are enabled/disabled simultaneously. (Setpoint = desired flow temperature *rSetPtTemp*, actual value = supply temperature *rFdT*).\ The control signals of both power controllers are fed through a minimum-value selection (forwarding the signal with the smaller value) to the output controller in the range -100.0 - 100.0 %.\ The output controller finally generates output signals for a 3-point actuator (pulse width modulation, integration interval = **tIntegration**) with the outputs *xMoreHB* or *xLessHB*.\ The constant pulse duration for the two outputs is freely adjustable in each case (**tImpulsOpen** or **tImpuls Close**), the variable pulse pauses are determined by the output controller.\ The two power controllers can be configured individually and independently of each other (P-controller fast: gain factor **rKpBig**, P-controller slow: gain factor **rKpTiny**). #### Manual override of the digital outputs All digital control outputs after manual override (*xHB*, xMoreHB\*, *xLessHB*) can either be operated in automatic mode (eMANBIN.Auto) or in one of the two manual operating modes (eMANBIN.ManOn, eMANBIN.ManOff). | *xAB* | eMANBIN | *xHB* | Notes | | ----- | -------------- | ----- | ---------------------------------------------- | | FALSE | eMANBIN.Auto | FALSE | Manual override module in automatic | | TRUE | eMANBIN.Auto | TRUE | Manual override module in automatic | | X | eMANBIN.ManOn | TRUE | Manual override module in manual operation On | | X | eMANBIN.ManOff | FALSE | Manual override module in manual operation Off | Legend: X = any #### Aggregate fault *xAlarm* The aggregate fault *xAlarm* is active (= TRUE) if the fault signal of the heat generator *xAlarmIn* is active (= TRUE).\ In all other situations the aggregate fault *xAlarm* not active (= FALSE). #### Collective automatic-mode message *xAuto* The collective automatic-mode message *xAuto* is activated (= TRUE) if the following conditions are met simultaneously: * Input *eAOO* = HVACTYPES.eManBin.Auto * Input *eAOOMore* = HVACTYPES.eManBin.Auto * Input *eAOOLess* = HVACTYPES.eManBin.Auto * Setpoint / parameters **eManModeB** = eMANBIN.Auto * Setpoint / parameters **eManModeBMore** = eMANBIN.Auto * Setpoint / parameters **eManModeBLess** = eMANBIN.Auto #### Operating hours counter - heat generator The operating hours counter (*udiOperatingHours*, *udiCountFb*) for the heat generator is active when the running signal is active (*xFb* = TRUE). > **Write access to the counter values** > > Via the path 'InstanceName.\_OperatingHours.udiOperatingHours' or 'InstanceName.\_OperatingHours.udiCountFb' write access to both counters is possible. > > **Prerequisite for the use of the function block Burner3P** > > The use of the TimeRead2 function block is required for correct operation. #### Current calculated power of the heat generator *rPos* The current **calculated power** of the heat generator is displayed at the output *rPos* in the range 0.0 - 100.0 %.\ For this, the correct specification of the travel time of the actuator between minimum and maximum power (**tDuration**) is required.\ No repositioning to a reference position takes place. #### Feedback of the heat generator power *rU* The current **actual** Power of the heat generator can be connected at the input *rU* .\ This input is currently not used for control and regulation purposes. #### Not active state (*xEn* = FALSE) | *xHB* | *xAB* | *xMoreHB* | *xMoreAB* | *xLessHB* | *xLessAB* | *rPos* | *tOnDelay* | *tOnControlDelay* | *dtLastFb* | *udiOperatingHours* | *udiCountFb* | *xAlarm* | *xAuto* | Notes | | -------------------------------- | ----- | ------------------------------------ | --------- | ------------------------------------ | --------- | ------ | ---------- | ----------------- | ---------- | ------------------- | ------------ | ------------------- | --------- | ------------- | | FALSE (eManModeB = eManBin.Auto) | FALSE | FALSE (eManModeBMore = eManBin.Auto) | FALSE | FALSE (eManModeBLess = eManBin.Auto) | FALSE | 0.0 % | old value | old value | old value | old value | old value | State of *xAlarmIn* | old value | *xEn* = FALSE | Legend: X = any ### CODESYS InOut: | Scope | Name | Type | Initial | | ----------- | -------------------- | ------- | ------------ | | Input | `xEn` | `BOOL` | | | Input | `rSetPtTemp` | `REAL` | | | Input | `xFb1` | `BOOL` | | | Input | `xFb2` | `BOOL` | | | Input | `xAlarmIn` | `BOOL` | | | Input | `eAOO1` | eManBin | eManBin.Auto | | Input | `eAOO2` | eManBin | eManBin.Auto | | Input | `rFdT` | `REAL` | | | Output | `xHB1` | `BOOL` | | | Output | `xAB1` | `BOOL` | | | Output | `xHB2` | `BOOL` | | | Output | `xAB2` | `BOOL` | | | Output | `tOnDelay` | `TIME` | | | Output | `tOn2Delay` | `TIME` | | | Output | `dtLastFb` | `DT` | | | Output | `udiOperatingHours` | `UDINT` | | | Output | `udiCountFb` | `UDINT` | | | Output | `dtLastFb2` | `DT` | | | Output | `udiOperatingHours2` | `UDINT` | | | Output | `udiCountFb2` | `UDINT` | | | Output | `xAlarm` | `BOOL` | | | Output | `xAuto` | `BOOL` | | | Input Const | `udiTimeTOFxFb` | `UDINT` | 7 | | Input Const | `udiWait2` | `UDINT` | 3 | | Input Const | `rSwitchOffPoint1` | `REAL` | 2.5 | | Input Const | `rSwitchOffPoint2` | `REAL` | -1 | | Input Const | `rSwitchOnPoint1` | `REAL` | -2.5 | | Input Const | `rSwitchOnPoint2` | `REAL` | -1.5 | | Input Const | `udiTimeMinOff` | `UDINT` | 3 | | Input Const | `eManModeB2` | eMANBIN | eMANBIN.Auto | | Input Const | `eManModeB1` | eMANBIN | eMANBIN.Auto |