EN stock discrepancy

Preamble

No hardware and no software can detect and display the 100% actual state in and of the tanks. Even probes in the tanks are subject to variances up to 3%, due to physical and thermal influences on the tanks and pumps.

Therefore the stock values displayed in Autopoll are only calculated values on the base of manually read stock values, tank probe values, deliveries and fillings booked in Autopoll or polled from the card readers. The calculation can only be an approach to the actual state in the tanks.

Calculation method

Autopoll calculates the stocks on the base of the last booked stock value or of the last booked or polled tank probe value, added by the following booked deliveries and subtracted by the following booked and/or polled fillingss.

Example:

* booked stock value 01.08.2015 00:00:	8.037	L
* deliveries after 01.08.2015 06:00:	+ 23.488	L
* fillings after 01.08.2015 06:00:	- 27.337	L
* other bookings (e.g. calibration service, tank cleaning etc.) after 01.08.2015 06:00:	- 0	L
* calculated stock 01.09.2015 00:00:	4.188	L
* polled probe value 01.09.2015 00:00:	3.959	L
* difference/discrepancy	- 229	L = 0,84 %

Interpretation:

On 01.08.2015 00:00 a tank content of 8.037 liters was detected and booked as "contents" in Autopoll. After that and before 01.09.2015 00:00 a total of 23.488 liters was delivered and a total of 27.337 liters was filled. The result is a new calcualted content of 4.188 liters. The probe in this tank delivers on 01.09.2015 00:00 a measured value of 3.959 liters. The discrepancy is -229 liters. In relation to the filled quantity (27.337 liters) the discrepancy has a percentage of 0,84 %.

Possible reasons for stock discrepancies:

Natural loss

Discrepancies of up to 1-2 % of the quantity of sales can occur due to temperature fluctuations (during the deliveries, in the tanks, while filling) and can only be avoided by temperature compensated fillings (temperature compensated pumps). ==> see Autopoll expansion temperature compensation

Data loss

To avoid data loss the function "Gaps Check" was implemented from Autopoll version 3.5 on. (Actions-Gaps Check) Card readers normally have consecutively numbered fillings. (e.g. 1-999) This function checks the filling or process number of the stored fillings whether there are gaps or not. ==> see Autopoll function Gaps Check

Data manipulation

Apparent losses can also occur when fillings have/had been manipulated in Autopoll.

Example:

The quantity of a filling was changed.

* Original quantity:	500	L
* Quantity after the change:	100	L
* Loss:	400	L

Fillings can only be changed/edited by Autopoll users with the corresponding rights. It can be configured in Autopoll that these changes can be recorded. (But only which Autopoll login has done which changes)

Imprecisely adjusted pumps

Public fuel stations have to be checked regularly by the calibration office. Privat fuel stations do not need these official calibrations at all. Pumps which are not being checked and calibrated regularly can work imprecise.

Stealing

b) wrong delivered quantity

To avoid that the quantity on the delivery note is not the same as really pumped into the tank, it is recommended to ask the supplier to create/print a "zero-bon" before starting the filling of the tank. Additonally it is recommended, if a tank probe is installed, to do a measurement shortly before the delivery and shortly after the end of the delivery (maybe it is necessary to wait after the end of the delivery a short time so that the liquid in the tank can settle down) so that the filled in quantity can be determined. But this is also only an approach because of the variance of the tank probe. (see above)

c) taking/filling at free-autarc pumps

In such cases no fillings will be recorded in the card reader and can't be transmitted to Autopoll. The only possibility to check and control these fillings is to observe, monitor and note the numbers of the counting devices directly at the pumps and compare these figures with the quantities in Autopoll. ==> see Autopoll tool pump control

Reduction of discrepancies

• Making regular manually stock measurements and booking these with the exact date and time as "contents" in Autopoll "stock movements". Minimum: once a year (Beginning or end of the financial year). Recommended: once per quarter. The more of these "contents" are being booked the lower are the discrepancies caused by the temperature compensation.

• Entering ALL deliveries with the exact date and time (end of the delivery)

• NOT deleting any fillings polled from the card readers.

• The quantity of fillings done during calibration services (because the filled quantities will be put back in the corresponding tanks) and afterwards polled to Autopoll should be reduced to 0 and the original quantity with a remark like "calibration" should be entered in the comment field of the filling (max. 30 characters).

• Regular checks: "fillings without assignment" and "Gaps Check".