How the System Calculates Projected Start Dates

The Maintenance Rules program (P1393) includes these fields on Maintenance Rules (W1393A), which relate to calculating start dates for work orders:

• Projected Start Date Method

• Sampling Amount

• Date - Projected From

Use the Projected Start Date Method field to specify how the system calculates the new start date for work orders. Methods are:

• Sampling Days method

  This method uses the number of days value that is entered in the Sampling Amount field to retrieve past F0911 table transactions; the default value is 365 days. This method also uses the date in the Projected Date - From field; the default value is the Last Completed Date.

  The system determines the change in meter readings based on the earliest and latest readings in the Sampling Days time period. A daily average is calculated by taking the change in meter readings and dividing this number by the number of days between the earliest and latest meter transactions in the date range.

  To project the start date, the system uses the daily average to calculate how many days remain until maintenance is due.

• Sampling Readings method

  This method uses the number of readings value that is entered in the Sampling Amount field to retrieve past F0911 table transactions; the default value is 5 meter readings. This method also uses the date in the Projected Date - From field; the default value is the Last Completed Date.

  The system determines the number of days between the earlier and latest meter readings. A daily average is calculated by taking the number of readings divided by the number of days.

  To project the start date, the system uses the daily average to calculate how many days remain until maintenance is due.

• Percent Due method

  This method uses the percent due of the preventive maintenance schedule and determines how many days it took to get to that point. The system calculates this percentage by taking the current meter reading and subtracting it from the last completed meter reading. The result is then divided by the service interval to obtain the percentage.

  To project the start date, the system calculates the remaining days by using the remaining percent and determining how many days it takes to reach 100 percent.

Use the Sampling Amount field for both the Sampling Days method and the Sampling Readings method to specify how many days or readings the system looks back in the Account Ledger when calculating new start dates for work orders.

Use the Date - Projected From field to specify the date that the system uses in projecting start dates. You can select either the Last Completed Date or the Through Date.