CounterMonitoring

CounterMonitoring (FB)

FUNCTION_BLOCK CounterMonitoring

Short description

Monitoring of a counter reading and generation of a fault message Typical application: Monitoring a water meter for exceeding a maximum consumption during a monitoring interval

Representation

Interfaces

Inputs

Name	Data type	Value range	Initial value	Function
xEn	BOOL		FALSE	Enable / disable the counter monitoring (TRUE = enabled)
rCounterValue	REAL		0.0	Current absolute counter value (e.g. meter for water volume)
xResetAlarm	BOOL		FALSE	Reset of the output 'xAlarm' (on each rising edge)

Outputs

Name	Data type	Value range	Initial value	Function
xAlarm	BOOL		FALSE	Fault message - counter monitoring (FALSE = off, TRUE = on)
tMonIntervall	TIME			Duration of a monitoring interval
tRemainIntervall	TIME			Remaining time in the monitoring interval
rConsumMax	REAL			Maximum consumption in the monitoring interval
rConsumIntervall	REAL			Current consumption in the monitoring interval
rConsumRemain	REAL			Remaining consumption in the monitoring interval before the alarm is triggered

Setpoints / parameters

Name	Data type	Value range	Initial value	Function
udiMonIntervall	UDINT		24	Duration of a monitoring interval (0 … 4294967295)
tMinIntervall	TIME		T#0s	Absolute minimum duration of a monitoring interval
tMaxIntervall	TIME		T#7D	Absolute maximum duration of a monitoring interval
eScaleIntervall	eTime		eTime.Hour	Scaling of the duration 'udiMonIntervall'
rConsumLimit	REAL		10.0	Limit value for consumption in the monitoring interval

Function description

General

This function block is used to monitor a media consumption (water, electricity, etc.) (input 'rCounterValue') during the configurable monitoring interval 'tMonIntervall'. If the consumption exceeds the maximum value for the monitoring interval 'rConsumLimit', an alarm ('xAlarm' = TRUE) is triggered. It can be reset by a rising edge on the input 'xResetAlarm'.

Monitoring

The cyclic monitoring interval starts if all of the following conditions are met simultaneously:

1. 'xEn' = TRUE

2. 'rConsumLimit' > 0.0

3. 'tMonIntervall' >= T#60s

The cyclic monitoring interval is terminated if at least one of these conditions is no longer met. At the start of each monitoring interval the current counter value 'rCounterValue' is stored as the start value. During the monitoring interval the difference between the current counter value and the start value is continuously calculated (rConsumIntervall). The output xAlarm is activated (= TRUE) whenever this difference exceeds the threshold rConsumLimit. The output xAlarm is reset (= FALSE) by each rising edge at the input 'xResetAlarm'. The setting of the duration 'tMonIntervall' is made by the set values 'udiMonIntervall' (absolute numeric value) in combination with 'eScaleIntervall' (scaling) taking into account 'tMinIntervall' (absolute minimum) and 'tMaxIntervall' (absolute maximum).

Indicators

The following outputs are available to display the current operating status:

1. xAlarm Fault message - counter monitoring (FALSE = off, TRUE = on)

2. tMonIntervall Duration of a monitoring interval

3. tRemainIntervall Remaining time in the monitoring interval

4. rConsumMax Maximum consumption in the monitoring interval (identical to rConsumLimit)

5. rConsumIntervall Current consumption in the monitoring interval (only consumptions >= 0.0 are displayed)

6. rConsumRemain Remaining consumption in the monitoring interval before the alarm is triggered (only consumptions >= 0.0 are displayed)

Locking of the block (xEn = FALSE)

These outputs take the following fixed states:

1. xAlarm FALSE

2. tMonIntervall T#0s

3. tRemainIntervall T#0s

4. rConsumMax 0.0

5. rConsumIntervall 0.0

6. rConsumRemain 0.0

CODESYS

InOut:

Scope	Name	Type	Initial
Input	xEn	BOOL	TRUE
Input	rCounterValue	REAL	0.0
Input	xResetAlarm	BOOL	FALSE
Input Const	rConsumLimit	REAL	10.0
Input Const	eScaleIntervall	eTime	eTime.Hour
Input Const	tMaxIntervall	TIME	TIME#10080m0s0ms
Input Const	tMinIntervall	TIME	TIME#0ms
Input Const	udiMonIntervall	UDINT	24
Output	xAlarm	BOOL
Output	tMonIntervall	TIME
Output	tRemainIntervall	TIME
Output	rConsumMax	REAL
Output	rConsumIntervall	REAL
Output	rConsumRemain	REAL