FilterMonitoringA

FilterMonitoringA (FB)

FUNCTION_BLOCK FilterMonitoringA

Short description

Detection of filter contamination and generation of an alarm message Typical application: Monitoring the contamination of an air filter with a differential pressure sensor

Representation

Function description

General

This function block is used to detect filter contamination by evaluating the input from the differential pressure sensor rPressure. If the differential pressure exceeds rPressure during the alarm delay udiControlTime permanently the threshold value rControlPressure, ( prerequisite: release of the monitoring xControl is active ( = TRUE )) then the alarm output xAlarm becomes active ( = TRUE ).

Enable monitoring xControl

Monitoring can generally be enabled ( = TRUE ) or disabled ( = FALSE ). If monitoring is not enabled, the output - alarm message xAlarm is deactivated ( = FALSE ) and the time duration until the triggering of the alarm message tTimeToAlarm takes the value 0s.

Output - pre-alarm xPreAlarm

The output - fault message xPreAlarm is activated ( xPreAlarm = TRUE ), if the condition 1 below is fulfilled. Condition 1: The input from the differential pressure sensor rPressure is greater than the maximum permissible differential pressure rControlPressure ( = filter contamination ).\

Output - fault message xAlarm

The output - fault message xAlarm is activated ( xAlarm = TRUE ), if the condition 1 below is fulfilled. Condition 1: The input from the differential pressure sensor rPressure is at least during the alarm delay udiControlTime permanently greater than the maximum permissible differential pressure rControlPressure ( = filter contamination ). At the same time, monitoring is generally enabled ( xControl = TRUE ). The output - alarm message xAlarm is deactivated in the following cases ( xAlarm = FALSE ): Case 1: Condition 1 is not met and the reset of the alarm message xQuit is active ( = TRUE ). Case 2: Condition 1 is not met and the enabling of the monitoring xControl is not active ( = FALSE ).

Time duration until triggering of the fault message tTimeToAlarm

At the output tTimeToAlarm different values are displayed depending on the operating situation: Situation 1: Output of the remaining time until the triggering of the alarm message ( conditions: rPressure > rControlPressure, xControl = TRUE ) Situation 2: If Situation 1 does not apply, then the value 0.0 is output permanently.

CODESYS

InOut:

Scope	Name	Type	Initial
Input	rPressure	REAL
Input	xAlarmSensor	BOOL
Input	xQuit	BOOL	FALSE
Input Const	rMaxControlPressureVisu	REAL	500
Input Const	rMinControlPressureVisu	REAL	10
Input Const	udiControlTime	UDINT	300
Input Const	rControlPressure	REAL	200
Input Const	xControl	BOOL	TRUE
Output	xAlarm	BOOL
Output	xPreAlarm	BOOL
Output	tTimeToAlarm	TIME