Brands     Vishay Measurements Group     Strain Gages     Modulus Compensation (EMC) Option
Transducer-Class Strain Gages Modulus Compensation (EMC) Option Many of the K-alloy gages are available in a special form which permits the gage factor change with temperature to be adjusted over a wide range during gage manufacture. Properly matched to the transducer spring element, these EMC (Effective Modulus Compensation) gages can provide very good self-correction of changes in transducer span versus temperature. A compensation better than ±0.0008%/°F (±0.0014%/°C) can readily be achieved in many cases. While this may at first appear to be the "ideal" strain gage for transducers, there are certain factors that should be considered prior to selecting EMC gages for a given application: EMC gages cost more than other gages. In most cases the difference is great enough to offset the additional cost of span/temperature resistors.   EMC gages must be "matched" to the transducer spring material. Depending on the degree of compensation accuracy desired, the standard EMC options may not yield the "best fit" compensation on the spring material in use. In these cases, a special foil lot which possesses the desired compensation would be required. There is normally a minimum order requirement and set-up charge for special foil lots.   Transducer spring materials may not have batch-to-batch repeatability sufficient to maintain specifications when using the same EMC gages. New material lot testing is therefore necessary for high precision units. Despite these limitations, EMC gages can often be advantageous for transducer manufacturers. The following standard EMC options are available: OPTION Ml Gage factor slope is -1.50% per 100° F (-2.70% per 100° C). Provides span-versus-temperature compensation for many stainless steels. OPTION M2 Gage factor slope is -2.35% per 100° F (-4.23% per 100° C). Provides span-versus-temperature compensation for most aluminum alloys. OPTION M3 Gage factor slope is -1.25% per 100° F (-2.25% per 100° C). Provides span-versus-temperature compensation for many tool steels. OPTION M4 Gage factor slope is -1.35% per 100° F (-2.43% per 100° C). Provides "mid-range" compensation between M1 and M3.