ISO 9000 procedures favor the calibration of balances with an external certified calibration mass.

A balance with internal motorized calibration weight is a nice feature, but costly.  Most balances with the internal calibration feature also offer external calibration.

External calibration is vital since it is much for convenient to send out the external calibration mass for recalibration/certification verses the costly fee of having the internal calibration mass removed from the balance and sent out for re-calibration.

In addition, if you own several of the same analytical balances just one external traceable calibration is needed for ISO compliance.

Precision Weighing Balances always recommends that you purchase the calibration weight with any balance you select.  This allows you to calibrate the balance yourself without requiring the services of an outside calibration firm.  Best of all calibration couldn't be simpler.

Scientech balances are a cinch to calibrate.  Turn ON the balance and allow the unit to warm as specified in the operators manual, press the keypad button related to calibration, the balance displays "CAL 0", nothing should be on platform (this is calibrating the unit with nothing on the platform), after a moment the balance will display the calibration mass needed: (CAL "XXX"), at this time place the calibration mass on the platform, press the keypad button related to calibration and your done.

The unit is now calibrated.

There is no certificate of calibration included with any balance we sell since this can only occur at the place of installation.  Every location in the world is positioned differently to "magnetic north" and therefore the acceleration of gravity is slightly different.  Add to this barometric pressure effects the acceleration of gravity depending upon your location's altitude to sea level.  Therefore the only way to attain a certificate of calibration is to do it yourself with a certified calibration mass which we sell.  You can basically copy the calibration instructions in the manual and create a QAD (Quality Assurance Directive), QAP (Quality Assurance Procedure) or SOP.  You can also create your own calibration procedure from scratch like this one here.  The other option would be to hire an outside calibration company to come out to the location where the balance is being used and perform the calibration.

People sometimes call us saying a competitor or catalog company offered to ship their balance with a calibration certificate if they purchase the balance from them.  Companies offering balance(s) with a calibration certificate are giving false documents unless the calibration is performed on site.  Sure, companies can sell a oscilloscope or power supply with a certificate of calibration when the power supply is calibrated halfway across the country since a power supply isn't effected by the different longitude and latitude of magnetic north like a balance.

Looking for calibration weights?  Check out our selection

The days of opening the balance and tweaking those potentiometers and trim resistors to calibrate a scale are gone with the advent of the digital circuit and EPROM technology.

Our best selling precision weighing balance line is the Scientech brand.  Any of the Scientech SA Analytical Series can be purchased with the optional internal calibration mass (part # 9000-INT.)  This appealing accessory allows you to quickly and easily recalibrate your balance as often as you wish without having to use an external calibration weight. 

The internal calibration is a nice feature, but we actually recommend purchasing balances without an internal motorized calibration.  The reason is it is just one more toy for people to play with and break.  In addition, most balances with an internal calibration check the servo motor for the internal calibration on power-up.  If the internal calibration system is not operating properly you can't even get past the power-up sequence without getting an error code.  If you can't get past the power-up sequence you can't use your balance.

The place of installation contributes to factors on how your balance reads a mass.  Barometric pressure, ambient temperature, humidity, altitude and the longitude and latitude of your location in reference to magnetic north results in variations of the gravitation force.

The above factors can result in slight variations of the results in possible weighing errors.

Calibrating the balance can eliminate these factors.  Daily calibration is also Good Laboratory Practice.  The picture below depicts some of these environment factors that can effect the performance of you precision weighing balance.

Finally, most quality assurance procedures along with GLP/GLP and ISO specifications clearly specify external calibration only.  All Scientech balances are GLP/GMP/ISO compatible.  Either using a computer or Scientech's optional data input keyboard and one of our small, optional RS232 printers, you may print a hardcopy of either the GLP/GMP Compliance Report and/or a Balance Test for ISO calibration compliance anytime you desire