If you operate as an LPG gas reseller or distributor from a shop, your digital weighing scale is one of the most important pieces of equipment you use when selling gas by weight.
Over time, a digital scale may begin to show readings that are not accurate. It may also need calibration after repairs, relocation or other changes. This is why LPG retailers need to understand the basic calibration process and also know when professional help is required.
This guide explains the common calibration procedure used on some digital weighing scales, including the 8620 tare calibration code, in simple terms.
Important: The exact buttons, calibration code and menu sequence depend on the make and model of the digital scale. The procedure below should only be used where it matches the instructions for your particular scale.
What Does Calibration Mean on a Digital Scale?
Calibration is the process of checking and adjusting a weighing instrument so that its displayed reading corresponds correctly with a known reference weight.
For an LPG retail shop, this matters because customers are buying LPG according to weight. A scale that is not properly adjusted can give a reading that is different from the actual weight.
Nigeria Department of Weights and Measures under the Federal Ministry of Industry, Trade and Investment is responsible for legal metrology, including the testing, verification and certification of weighing and measuring instruments used in commercial transactions.
So, calibration should not be confused with official verification or certification.
Before You Start Calibration
You need a known reference weight suitable for the capacity and manufacturer's instructions for the scale.
For example, some procedures may use a known weight of 5kg or more, but the appropriate calibration weight depends on the particular scale.
You should also know the maximum capacity of the scale.
For example:
- 100kg scale
- 150kg scale
- 300kg scale
- Or another capacity specified by the manufacturer
Do not guess the capacity or calibration settings. Check the scale label, manual or manufacturer specification.
Common 8620 Calibration Sequence
On compatible digital scales, the calibration sequence may use the following code:
8620 - TARE - 1 - TARE
After entering the calibration mode, the scale may ask for several settings.
Step 1: Enter the calibration code
Enter:
8620
Then press:
TARE
The scale should move into the calibration setting if this code is supported by that particular model.
Step 2: Place the known reference weight
Place the appropriate known reference weight on the weighing platform.
The scale needs a known weight so that it can establish the relationship between the actual weight and the value shown on the display.
For example, if the reference weight being used is 5kg, the scale needs to recognize that the weight placed on the platform is 5kg.
Step 3: Enter the scale capacity
The next setting may require the maximum capacity of the scale.
For example, a scale may have a capacity of 100kg, 150kg or another specified capacity. Next, enter the capacity according to the scale's actual specification and then press TARE.
Step 4: Select the decimal places
The scale may then ask how many decimal places you want displayed.
For example:
> 2 decimal places: 5.00kg
or
> 3 decimal places: 5.000kg
Select the display format required by the scale and press TARE.
The number of decimal places is simply about how the measurement is displayed. It does not automatically make an inaccurate scale accurate.
Step 5: Select the weighing/counting format
Some digital scales may also ask for the reading interval or counting format. Depending on the model, you may see options such as:
2 or 5
This determines how the scale displays or increments its readings. Select the appropriate setting for the particular scale and press TARE.
Step 6: Complete the calibration
After the required settings have been entered, the scale should complete the calibration process and return to its normal weighing mode.
Remove the reference weight and allow the display to return to zero. The scale can then be checked against the known reference weight again to confirm that the displayed reading is consistent.
Why LPG Retailers Need an Accurate Scale
For an LPG reseller, the digital scale is not just another shop accessory. It is the equipment used to determine the quantity being sold to the customer.
If a scale consistently reads too high or too low, it can create problems for both the retailer and the customer.
For example, if a known reference weight is placed on the platform and the scale does not give the expected reading, the scale should not simply be assumed to be correct.
The issue may be calibration, the weighing platform, the load cell, the power supply, physical damage or another fault.
Calibration Is Not the Same as Official Verification
This is an important point for LPG retailers.
Remember that calibrating a scale yourself does not automatically mean that the scale has been officially verified or certified for commercial trade.
The Federal Ministry Weights and Measures Department oversees legal metrology in Nigeria, including the verification and certification of weighing instruments used in commerce.
The Standards Organisation of Nigeria National Metrology Institute also provides calibration services and maintains Nigeria's national measurement standards and traceability system.
Therefore, if you are using a scale for commercial LPG sales, follow the applicable requirements for your business and location rather than relying only on the scale internal calibration menu.
One More Thing: The 8620 Code Is Not Universal
Many digital scales look similar, but their internal settings are not necessarily the same.
That means 8620 is not a universal calibration code for every digital weighing scale in Nigeria.
A different model may use another code, another button sequence or a completely different calibration procedure.
Before entering calibration mode, check the manufacturer's instructions or have the scale handled by a qualified technician familiar with that model.