The system performs the following,
Computes the Next Scheduled Date (NSD) in the following way, for tasks with calendar-based schedule:
NSD = Threshold Value + Reference Date (Induction date or Operational date)
If the Last Performed Date of the work unit is available,
Next Schedule Date = Last Performed Date + Repeat Fixed Interval/Repeat Floating Interval.
4 Computes the Next Scheduled Value (NSV) in the following way, for tasks with usage-based schedule:
If the Last Performed Value of the work unit is not available,
NSV = Threshold Value (if the Threshold Value is greater than the current value of the parameter)
If the Last Performed Value of the work unit is available,
NSV = Last Performed Value + Repeat Fixed Interval / Repeat Floating Interval.
However, if the Threshold Value is available for one or more parameters and if the Repeat Fixed Interval/Repeat Floating Interval is available for more than one parameter, the system computes the NSV as illustrated by an example.
Usage-based schedule values as on 20th July, 2009
Parameter
Threshold Value
Repeat Fixed Interval/Repeat Floating Interval
NSV
FH
100
NULL
100
FC
NULL
50
NULL
EH
NULL
250
NULL
APUH
NULL
250
NULL
Let us assume the FH parameter reached 100 on 22nd July, 2009 and the task was compiled on the same day in accordance with the schedule in the maintenance program. The attribute values (indicated by the Last Performed Value) recorded on 22nd July, 2009 for the calendar-based schedule are as given below.
Parameter
Last Performed Value
Threshold Value
Repeat Fixed Interval/Repeat Floating Interval
NSV
FH
100
100
NULL
NULL
FC
20
NULL
50
70
EH
95
NULL
250
345
APUH
55
NULL
250
305
4 Computes the NSD and NSV in the following way, for tasks with both calendar-based and usage-based schedules, on the basis of the attributes available including Last Performed Date, Last Performed Value and Repeat Fixed Interval/Repeat Floating Interval. More details
Scenario 1: Calendar-based schedule: Threshold Value available, Repeat Fixed Interval/Repeat Floating Interval not available. Usage-based schedule: Threshold Value not available, Repeat Fixed Interval/Repeat Floating Interval available.
Date-based schedule values as on 20th July, 2009
Threshold Value
Repeat Fixed Interval/Repeat Floating Interval
NSD
3 Days
NULL
23rd July, 200
Usage-based schedule values as on 20th July, 2009
Parameter
Threshold Value
Repeat Fixed Interval/Repeat Floating Interval
NSV
FH
NULL
225
NULL
FC
NULL
50
NULL
EH
NULL
250
NULL
APUH
NULL
250
NULL
We assume the task was compiled on 23rd July, 2009 and the values recorded for usage-based parameters on the compiled date are, as given below.
Threshold Value
Last Performed Date
Repeat Fixed Interval/Repeat Floating Interval
NSD
3 Days
23rd July, 200
NULL
NULL
The updated attributes of the calendar-based schedule on 23rd July, 2009would be, as given below.
Parameter
Threshold Value
Las Performed Value
Repeat Fixed Interval/Repeat Floating Interval
NSV (Last Performed Value + Repeat Interval)
FH
NULL
200
225
425
FC
NULL
40
50
90
EH
NULL
225
250
475
APUH
NULL
225
250
475
Scenario 2: Calendar-based schedule: Threshold Value not available, Repeat Fixed Interval/Repeat Floating Interval available. Usage-based schedule: Threshold Value available, Repeat Fixed Interval/Repeat Floating Interval not available.
Date-based schedule values as on 20th July, 2009
Threshold Value
Repeat Fixed Interval/Repeat Floating Interval
NSD
NULL
3 Months
NULL
Usage-based schedule values as on 20th July, 2009
Parameter
Threshold Value
Repeat Fixed Interval/Repeat Floating Interval
NSV
FH
200
NULL
NULL
Let us assume the FH parameter reached 100 on 22nd July, 2009 and the task was compiled on the same day in accordance with the pre-defined schedule. The attribute values on 22nd July, 2009 for the calendar-based schedule were as follows,
Threshold Value
Last Performed Date
Repeat Fixed Interval/Repeat Floating Interval
NSD
NULL
22nd July, 2009
3 Months
22nd October, 2009
The attribute values on 22nd July, 2009 for the usage-based schedule were as follows,
Parameter
Threshold Value
Last Performed Value
Repeat Fixed Interval/Repeat Floating Interval
NSV
FH
200
100
NULL
NULL