Gas Volume Converters

An EVC is an electronic device fitted to a gas meter that converts the volume measured at line conditions into volume at base conditions. It reads the meter pulses, measures gas pressure and temperature, and applies a compressibility factor. A PTZ device corrects for pressure, temperature and compressibility together. The Modus and Modus Slim2 are MID certified PTZ converters for ATEX Zone 0.

Gas is compressible, so the same quantity takes less volume at higher pressure or lower temperature. A rotary or turbine meter measures the actual volume flowing at line conditions, while gas is billed at base conditions. Without correction, a meter running at several bar would record far less volume than was delivered. The converter applies the pressure, temperature and compressibility factors to give the billable volume.

The Modus accepts low frequency pulse inputs up to 3 Hz from a primary gas meter on each channel, and the second channel also accepts high frequency signals up to 5 kHz. This suits meters with low frequency reed outputs or high frequency sensors, such as the IM-RM and IM-TM, which offer both options.

On the Modus Slim2, yes: the flyer states that the battery can be replaced in the hazardous area without removing the metrological seal. Its internal lithium battery lasts more than 5 years with daily GSM/GPRS communication. The Modus runs about 5 years on its primary battery with one daily call, or from the MPower barrier for continuous communication.