About Days / Variances in Advance
The system uses the Days in Advance and Variances in Advance values in EM Work Order Initialize to determine which maintenance items are due.
The Day in Advance field applies only to those maintenance items with a basis of Hours, Miles/Kilometres, or Gallons/Litres, where scheduling includes a time interval (e.g. every 90 days). When selecting equipment for initialization, the system will first compare the equipment’s current hours, miles/kilometres, or gallons/litres with the maintenance item’s ‘last done’ hours, miles/kilometres, or gallons, and then use the service schedule (e.g. perform service every 3000 miles/kilometres) to determine if the equipment is due for maintenance. If the equipment does not meet the service schedule requirements (defined for the maintenance group), the system will then compare the Days in Advance with the maintenance item’s Last Done Date and the time interval to determine if the equipment is due for maintenance. Equipment meeting either of these requirements will be added to the grid.
For example, in EM Standard Maintenance Groups you set up a maintenance item that is scheduled to be performed every 3000 miles/kilometres or every 90 days on a piece of equipment. The last maintenance (i.e. last done date) was performed June 30th , with the odometer reading 10,000 miles/kilometres. The next maintenance is due at 13,000 miles/kilometres or on September 30th (whichever comes first). On September 15th, you run this program and specify ‘20’ as the Days in Advance. The odometer reading for the piece of equipment is only at 12,000 (1,000 miles/kilometres till due for maintenance); therefore, the system looks to see if a time (days) interval was specified (in EM Standard Maintenance Groups) and compares it with the Days in Advance value. In this case, the interval is 90 days, which is 15 days from being due and which falls within the 20 days specified in the Days in Advance field. Therefore, the item will be included on the list.
The Variances in Advance field applies to maintenance groups for which a 'warning' interval has been specified (in EM Standard Maintenance Groups), and is a multiple of the actual variance amount.
For example, say an item is due for maintenance every 3000 miles/kilometres and you want to be warned when the equipment is within 200 miles/kilometres of being due for maintenance (the variance). The last time maintenance was performed, the equipment’s odometer was at 10,000 miles/kilometres, which means it is next due at 13,000 miles/kilometres. When you run this program, the odometer reads 12,500, which means it will be due for maintenance in another 500 miles/kilometres. If you enter “1” as the Variance In Advance, the system multiplies that by the warning interval specified for the maintenance item (1 x 200 = 200), then compares the value to the number of miles/kilometres till the equipment is actually due for maintenance (500). In this case, the 500 miles/kilometres do not fall within the specified 200-mile variance; therefore, the equipment will not be included on the list. However, if you enter “3” as the variance instead, the equipment will be included because the 500 miles/kilometres falls within the 600-mile variance (3 x 200 = 600).