Fancoil3Stage (FB)¶

FUNCTION_BLOCK Fancoil3Stage

Controls a fan coil unit with an N-stage fan (N 1..3)

For application examples and device examples see FancoilContinuous.

Functionality¶

Fancoil3Stage provides a control strategy for a fan coil unit with an N-stage fan (N 1..3). The fan is controlled either by:

control signal inputs - the heat / cool valve position setpoints compute by SequenceControl
control deviation related to active operation mode (eModeIn)

The Fancoil3Stage control strategy takes into account:

control of fan speed dependent on valve position or control deviation
minimum fan speed
delays switching from on stage to another one
fan follow-up time
coil pre-heat / pre-cool
control of optional condensate pump (cooling mode)
manual control of fan
manual control of valves

Control of fan speed dependent on valve position or control deviation¶

The fan can be controlled dependent on valve position or control deviation - default is dependent control deviation. Please be aware, that negative heating control deviation and positive heating control deviation should activate the fan. Usually a “dead zone” is supposed to be in between heating sequence and cooling sequence - for more details see SequenceControl. To setup the fan stage thresholds for fan control dependent control deviation choose rFanTresholdStage1Heat..rFanTresholdStage3Heat to appropriate heat deviation. Set rFanTresholdStage1Cool..rFanTresholdStage3Cool accordingly for cooling.

To setup the fan stage thresholds for fan control dependent valve position choose rFanTresholdStage1Heat..rFanTresholdStage3Heat with appropriate heat valve. Set rFanTresholdStage1Cool..rFanTresholdStage3Cool accordingly for cooling.

InOut:

Scope	Name	Type	Initial	Comment
Input	`xEnable`	`BOOL`	TRUE	Enable
	`usiNumStages`	USINT (1..3)	3	Number of stages - 1 .. 3
	`rHeatIn`	`REAL`		Heat control signal (0..100%).
	`rCoolIn`	`REAL`		Cool control signal (0..100%).
	`eModeIn`	HeatCoolOperationMode	HeatCoolOperationMode.UNUSED	Controller operation mode.
	`rDeviationMode`	`REAL`		Control deviation related to active operation mode - negative value for HEAT, positive value for COOL
	`xFanSpeedByDeviation`	`BOOL`	TRUE	Control fan speed dependent on control signal (FALSE) or control deviation (TRUE).
	`rFanTresholdStage1Heat`	`REAL`	-0.5	Treshold to enable fan stage 1 heating (in K for fan control dependent on control deviation, in % for fan control dependent on valve position)
	`rFanTresholdStage2Heat`	`REAL`	-1.0	Treshold to enable fan stage 2 heating
	`rFanTresholdStage3Heat`	`REAL`	-2.0	Treshold to enable fan stage 2 heating
	`rFanTresholdStage1Cool`	`REAL`	0.5	Treshold to enable fan stage 1 cooling (in K for fan control dependent on control deviation, in % for fan control dependent on valve position)
	`rFanTresholdStage2Cool`	`REAL`	1.0	Treshold to enable fan stage 2 cooling
	`rFanTresholdStage3Cool`	`REAL`	2.0	Treshold to enable fan stage 2 cooling
	`rFanHysteresis`	`REAL`	0.2	Fan stage hysteresis (0..INF K for fan control dependent on control deviation, 0..100 % for fan control dependent on valve position) Fan control dependent on control deviation: fan stage is reduced if control deviation reaches threshold + rFanHysteresis (heat) resp. threshold - rFanHysteresis (cool). Fan control dependent on valve position: fan stage is reduced if valve position reaches threshold + rFanHysteresis.
	`tFanDelay12`	`TIME`	TIME#0ms	Delay to switch stage 1 => stage 2
	`tFanDelay23`	`TIME`	TIME#0ms	Delay to switch stage 2 => stage 3
	`tFanDelay32`	`TIME`	TIME#0ms	Delay to switch stage 3 => stage 2
	`tFanDelay21`	`TIME`	TIME#0ms	Delay to switch stage 2 => stage 1
	`tFanFollowUp`	`TIME`	TIME#2m0s0ms	Fan follow-up time - continue to run in stage 1 beyond request.
	`tPreHeat`	`TIME`	TIME#0ms	Coil pre-heat time.
	`tPreCool`	`TIME`	TIME#0ms	Coil pre-cool time.
	`xCpumpErri`	`BOOL`	FALSE	Condensate pump error indication - condensate pump is signaling an error
	`rHeatManual`	`REAL`	0.0	Heat valve manual control (0..100%).
	`xHeatManual`	`BOOL`	FALSE	Heat valve manual control used.
	`rCoolManual`	`REAL`		Cool valve manual control (0..100%).
	`xCoolManual`	`BOOL`	FALSE	Cool valve manual control used.
	`usiFanStageManual`	USINT (0..3)	0	Fan speed manual control - 0 => off, or stage 1 .. 3
	`xFanStageManual`	`BOOL`	FALSE	Fan speed manual manual control used.
	`xReset`	`BOOL`	FALSE	Reset
	`itfDateTimeProvider`	`Util.IDateTimeProvider`	Globals.g_dtpDateTimeProvider	Source for the current date and time information in milliseconds since 1.1.1970 00:00:00.000
Output	`eModeOut`	HeatCoolOperationMode	HeatCoolOperationMode.INACTIVE	Operation mode.
	`rHeatOut`	`REAL`		Heat valve signal (0..100%).
	`rCoolOut`	`REAL`		Cool valve signal (0..100%).
	`xFanStage1`	`BOOL`		Fan stage 1
	`xFanStage2`	`BOOL`		Fan stage 2
	`xFanStage3`	`BOOL`		Fan stage 3
	`usiFanStageOut`	USINT (0..3)		Fan stage - 0 => off, or stage 1 .. 3 - supposed to be used in visualisation
	`eFanState`	Fan3StageState		Actual state
	`xCpumpOut`	`BOOL`	FALSE	Condensate pump.
	`xError`	`BOOL`		Error indication
	`eErrorID`	Error		Error ID