CtrlPiPulse (FB)

FUNCTION_BLOCK CtrlPiPulse EXTENDS AbbLConC3

This function block reacts as a PI step controller with digital pulse outputs to control two digital actuators. This is typically used in special HVAC applications with two different control properties e.g. heating and cooling.

Main features of the function block include-

• Pulse output

• Manual control mode

• Input procesing

• Feedback loop

• Three step hysteresis relay

• Pulse Generator

This Function Block performs as a PI step controller with digital pulse outputs to control 2 digital actuators.

The PLC task time (Unit: milliseconds) needs to be same as the “Cycle” (Unit :Seconds)input of the function block.

Note

The ActuatorTime needs to be > = 30 * Cycle, if not the ActuatorTime will be set to = 30 * Cycle internally

InOut:

Scope	Name	Type	Initial	Comment
Input	Sp	REAL	0.0	2: Set point input for PI step controller
	PvIn	REAL	0.0	3: Process variable input in floating point format
	PvIo	INT	0	4: Process variable in IO format, PvIn=(PvIo*100/27648) * PvFactor + PvOffset
	PvFactor	REAL	1	5: Process variable factor is used to adapt the process variable range
	PvOffset	REAL	0.0	6: Process variable offset is used to adapt the process variable range
	PvIoOn	BOOL	FALSE	7: Turn on process variable input channel in IO format with PvIo
	Deadband	REAL	0.0	8: Dead band of Error variable, Deadband>=0
	Ti	REAL	10	9: Time response of the integrator (Unit: Second) 10000.0>= Ti >= 0.1
	Kp	REAL	1	10: Propotional gain input sets of PI controller
	FfOffset	REAL	0.0	11: Feed forward offset for Manipulated variable
	ManualOn	BOOL	FALSE	12: Turn on manual mode for controlling PulseUp / PulseDown actuating signals: FALSE- Automatic mode, TRUE- Manual mode
	ManualUp	BOOL	FALSE	13: When Manual mode is on, generate actuating signal for “PulseUp” output manually.This should not be in combination with ManualDown.
	ManualDown	BOOL	FALSE	14: When Manual mode is on, generate actuating signal for “PulseDown” output manually.This should not be in combination with ManualUp.
	HighLim	BOOL	FALSE	15: Connect to high limit of position feedback signal, HighLim = True means the actuator is at upper limit stop
	LowLim	BOOL	FALSE	16: Connect to low limit of position feedback signal, LowLim = True means the actuator is at lower limit stop
	ActuatorTime	REAL	30	17: Motor actuating time is the time required by actuator to move from one limit stop to next limit stop.(Unit = Second), 10000 >= ActuatorTime > 0.1. Unit = Seconds.
	PulseWidth	REAL	3	18: Minimum pulse width (Unit: Second) PulseWidth>=0.The PulseUp Output should have a logic “one” pulse width >= PulseWidth Input.
	PulseBreak	REAL	6	19: Minimum pulse break (Unit: Second) PulseBreak>=0.The PulseDown Output should have a logic “zero” pulse width >= PulseBreak Input.
	Cycle	REAL	1	20: Cycle = PLC task cycle time (Unit: Second). Cycle>=0
Output	ErrorID	ERROR_ID		2: Error Code.Error identifier if an invalid value was applied to an input
	SpReached	BOOL	FALSE	3: Controlling state of the PI step controller, SpReached=TRUE means process variable (PV) reaches set point (SP)
	Pv	REAL	0.0	4: Process variable output of PI step controller
	Ev	REAL	0.0	5: Error variable of the set point and the process variable
	PulseUp	BOOL	FALSE	6: Pulse signal up, generates actuating signal to open actuating valve
	PulseDown	BOOL	FALSE	7: Pulse signal down, generates actuating signal to open actuating valve