FilterMonitoringA

FilterMonitoringA (FB)

FUNCTION_BLOCK FilterMonitoringA

Short description

Detection of a filter contamination and generation of a fault 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 reporting delay udiControlTime continuously the threshold value rControlPressure, (precondition: enabling of the monitoring xControl is active (= TRUE)) then the alarm output xAlarm becomes active (= TRUE).

Enable monitoring xControl

The monitoring can generally be enabled (= TRUE) or disabled (= FALSE). If monitoring is not enabled the output - fault message xAlarm is deactivated (= FALSE) and the time duration until the triggering of the fault 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 allowable 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 reporting delay udiControlTime continuously greater than the maximum allowable differential pressure rControlPressure (= filter contamination). At the same time the monitoring is generally enabled (xControl = TRUE). The output - fault message xAlarm is deactivated in the following cases (xAlarm = FALSE : Case 1: Condition 1 is not fulfilled and the reset of the fault message xQuit is active (= TRUE). Case 2: Condition 1 is not fulfilled and the enabling of the monitoring xControl is not active (= FALSE).

Time duration until the fault message is triggered tTimeToAlarm

At the output tTimeToAlarm show different values depending on the operating situation: Situation 1: Display of the remaining time duration until the triggering of the fault message (conditions: rPressure > rControlPressure, xControl = TRUE) Situation 2: If situation 1 does not apply, the value 0.0 is output continuously.

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