Mass Comparators | Instruments for the Determination of Mass

The MCM1005 has an electronic range of 610 g and a motorized automatic switching internal substitution weight of 500 g. Therefore, the mass comparator will be able to display correct values only in the electronic range, indicated mass values above 610 g are arbitrary. 

The MCM106 has an electronic range of 61 g and a motorized automatic switching internal substitution weight of 50 g. Therefore, the mass comparator will be able to display correct values only in the electronic range, indicated mass values above 61 g are arbitrary. 

The YCM20MC is an intelligent climate station, after it has been calibrated all values and adjustment data are stored on the integrated microprocessor, which means that once connected to a Cubis MCM Mass Comparator the correct values from the independently calibrated YCM20MC for temperature, humidity and air pressure are displayed.

The first time that the YCM20MC is connected to a Cubis MCM mass comparator this should be with the power turned off, firstly for good practice and secondly, when the power is turned on for the first time the comparator reads the data stored in the microprocessor of the YCM20MC climate module, then all values are displayed.

The YCM20MC is calibrated within the environmental range limits given in the OIML R111, however in some circumstances, such as La Paz and Mexico City with extreme altitudes, then the climate modules can be specially calibrated outside of the OIML range limits.

With mass comparators having readability 0.1 µg to 1 mg (up to 5kg) all models have an integrated draft shield, which is normally considered sufficient for calibration of weights up to class E2, the exception being if air currents, especially from air conditioning systems are influencing measurements.  For weight calibration at Class E1 or higher, then even with acceptable levels of air currents, the second external draft shield will protect from any operator thermal influences.  Mass Comparators from 10 kg upwards generally have an open pan and will need protection from even moderate air currents for calibration at F1 or above, for M class the influence from air currents has less influence on the allowable repeatability.

With Cubis MCM data can be transferred directly into Excel only when using additional software such as Win-Wedge.
If the MassCal App, included as standard with Cubis MCM, is used to perform the calibration routine, then the results data can be saved to an SD card and extracted as a CSV file, or fulfilled in a customizable Excel template.  Either the SD card can be transferred to a PC to be read, or the results can be accessed directly if the Cubis MCM Mass Comparator, with its own IP Address, is connected to a network.

The cost for an automatic mass comparator is higher, however there are many advantages:

• Typically, the resolution is ten time higher e.g. 1 kg x 1 µg as opposed to of 10 µg with a manual model.
• The human element is removed, so that weights are positioned and re-positioned more precisely during the calibration routines.
• Subdivision and dissemination routines are much easier and more repeatable as the groups of weights remain in the same position.
• The automatic mass comparators can operate 24 hours a day and overnight/weekend when the lab conditions are more stable.
• All of which contribute to lower uncertainty of measurement, especially required for class E1 or better routines.  Additionally more weights can be calibrated in a given time period, given that the automated mass comparators and especially Robotic Systems have large weight magazines.

This method is supported by OIML R111 and care is taken to set the height separation between the weights under test and the integrated magnet specific to the class of the calibration weight.  This ensures that if the material that the weight is made from complies with requirement of OIML that it will not become magnetized.  

The mass comparator is not a laboratory balance and is never used for absolute weighing, instead is used to measure precisely and accurately the difference between a traceable mass standard and a weight under test.  The calibration certificate from the reference weight provides traceability to a national standard for the calibration process.  However, a performance test certificate is included from final test and inspection covering important metrological parameters.