One of the most commonly-asked questions that accompany the purchase of a new balance is ‘When should I calibrate it for the first time, and how often should I calibrate it afterwards?’
– Although this is technically two questions, they are both absolutely vital for achieving the most accurate readings from a new balance or a set of scales – any operating manual would be remiss if it didn’t mention the need for calibration within the first section.
By following a few relatively simple steps during the lifetime of the equipment, it will remain in optimal working condition for the longest possible period of time.
The bottom line is: How important is the level of accuracy your application requires?
The obvious answer to this is dependant on application that the balances will be used for but as a rule of thumb, regular calibration is vitally important. Some applications require the highest degree of accuracy: gloves and tweezers should be used as even the grease from the users hands can cause inaccuracies along with other external contaminants such as dust or water vapour for example.
Regular calibration with precision calibration weights s vital. Correct weights must be used: conforming to Mass Standards E2, F1 and M1 for example to ensure that accuracy is maintained
There are a number of external factors than can affect the calibration of this type of device and as a rule of thumb, any unwanted factors that adjust the internal mechanisms of a balance or scale should be counteracted with a form of calibration.
Moving the device from one place to another, unpacking it after shipping, accidental knocks or damage, and even changes in air pressure can alter the accuracy of the equipment. If you are working in a lab where other users have access to your scales and balances, you should perform calibration on a regular basis for your own peace of mind – after all it is usually impractical for you to keep a personal watch over all of your equipment on a permanent basis.
As mentioned above, there are a number of situations which should act as a ‘trigger event’ for you to consider performing some kind of calibration process.
When you are unpacking your brand new scale or balance, you have in effect arrived at the first opportunity to undergo calibration. Bearing in mind that the measurement product could have been manufactured a great distance away from your laboratory or place of work, the factory conditions could be very different to your working environment – its new surrounding air pressure, temperature and environmental conditions need to be factored into the measurement process in order to get an accurate reading.
Aside from this, the actual shipping process could have led to the device receiving a number of knocks through rough handling and transportation, and each impact could have had a minor effect on the measurement mechanisms. With multiple impacts, there is a good possibility that the balance would have become significantly inaccurate. When dealing with equipment that is extremely sensitive, a change in location will also lead to a difference in the surrounding levels of gravity due to its relative position from the North or South Pole, and this is another reason why it is vital to perform calibration.
It can be advantageous to invest in a balance that comes equipped with internal motorised calibration, and this feature provides a convenient and automated process that allows the balance to adjust itself to new surroundings with the press of a button. The convenience of this type of calibration means that users can in effect perform the process each and every time the machine is switched on.
Apart from this method, it will also usually be possible to perform external calibration for the balance, and this involves taking a weight that has already been assigned a pre-determined value – this could be 1000g or a similarly-round value. Once the balance or scales is aware of this value, it can then measure other masses against this initial reading. For absolute peace of mind in situations where external calibration needs to be used, scientific professionals should consider obtaining pre-determined calibration weights that have already been weighed and certified.
When calibrating and using electronic balances and scales, there are a number of other factors that need to be taken into consideration – these will all increase the overall effectiveness of the equipment.
Users of sensitive equipment may already be aware that the device needs to be placed in an area that has little surrounding activity, and you should bear in mind that industrial machinery can often emit vibrations that will affect the weighing device. By ensuring that the device is resting on a surface that is completely flat (you can adjust the feet of the scales accordingly), you can also check to see that the device has been grounded by coming into contact with another metal surface to prevent static electricity from affecting the reading.
Our range of Laboratory Balance Accessories such as the anti-vibration table, covers and hard cases are ideal for aiding the accuracy and performance of your weighing equipment.
Within the Adam Equipment Range of scales and balances, all of the above features have been taken into consideration to allow users to obtain accurate measurements – this applies to both their portable/compact and conventional models. Their precision balances are supplied with a high standard of automatic internal calibration for the convenience of the user, while other scales can be supplied with the certified weights that make external calibration as accurate as possible.
In this range of equipment, moisture balances are also available that are specifically designed to analyse the unique properties that accompany moisture and liquids.