ServiceCounter

ServiceCounter (FB)

FUNCTION_BLOCK ServiceCounter

Short description

Signaling of maintenance

Representation

Interfaces

Inputs

Outputs

Name	Data type	Value range	Initial value	Function
dLastService	DATE			Date of the last maintenance
dNextService	DATE			Date when the next maintenance is due
xAlarm1	BOOL			Indication that maintenance is due soon
xAlarm2	BOOL			Indication that maintenance is due today
xAlarm3	BOOL			Indication that maintenance was already due
diServiceInDay	DINT			Indication of in how many days the next maintenance is due
diServiceSinceDay	DINT			Days since the last maintenance

Setpoints / parameters

Name	Data type	Value range	Initial value	Function
iAlarm1	INT	(0-diServiceInterval)…0	-10	Alarm threshold 1 in days (maintenance is due soon)
iAlarm3	INT	0…diServiceInterval	10	Alarm threshold 3 in days (maintenance was already due)
diServiceInterval	UINT	1…1825	365	Maintenance interval (in days)
xReset	BOOL		FALSE	Reset maintenance day counter
xEn	BOOL		TRUE	Enable outputs xAlarm1 to 3

Function description

General

This function block provides functionalities for signaling maintenance intervals and for resetting the counter after maintenance has been performed. The three signaling outputs can be temporarily disabled. The number of days until the next maintenance (maintenance interval) can be freely set. The number of days since the last maintenance is calculated and displayed.

Outputs xAlarm1, xAlarm2 and xAlarm3

With the setpoint / parameter xEn equal to FALSE the outputs are xAlarm1, xAlarm2 and xAlarm3 temporarily deactivated. When the next service interval expires, the setpoint / parameter is reset to the initial value TRUE. The output xAlarm1 will be TRUE when the next maintenance date is reached in less than iAlarm1 days. Because the period is before the maintenance date, the value is negative to be entered. The output xAlarm2 is TRUE when maintenance is due today (diServcieInDay <= 0). The output xAlarm3 is TRUE when the next maintenance date was at least iAlarm3 days ago. The three outputs are reset to FALSE when the maintenance day counter is reset with the setpoint / parameter xReset . The variable dLastService is overwritten with the current date.

Setpoints / parameters iAlarm1, iAlarm3 and diServiceInterval

The setpoints / parameters are provided with input limits according to the following table:

Setpoint / Parameter	Minimum value	Maximum value	Note
diServiceInterval	0	5 * diServiceInterval	Service interval
iAlarm1	(0-diServiceInterval)	0	Threshold for output xAlarm1
iAlarm2	iAlarm1	iAlarm3	Threshold for output xAlarm2
iAlarm3	iAlarm2	diServiceInterval	Threshold for output xAlarm3
The setpoint / parameter iAlarm2 cannot be changed by the user.

The setpoints / parameters are checked cyclically and limited to the corresponding limits if necessary. Any change to one setpoint / parameter can therefore cause a change to another setpoint / parameter.

Prerequisite for the use of the ServiceCounter function block

The use of the TimeRead2 function block is required for correct operation.

CODESYS

InOut:

Scope	Name	Type	Initial
Input Const	xEn	BOOL	TRUE
Input Const	xReset	BOOL	FALSE
Input Const	diServiceInterval	UINT	365
Input Const	iAlarm3	INT	10
Input Const	iAlarm1	INT	-10
Output	dLastService	DATE
Output	dNextService	DATE
Output	xAlarm1	BOOL
Output	xAlarm2	BOOL
Output	xAlarm3	BOOL
Output	diServiceInDay	DINT
Output	diServiceSinceDay	DINT