Gas density sensor with wireless transmission For gas density, temperature and pressure of insulating gases WIKA data sheet SP 60.78 Gas density sensor, model GD-20-W Applications ■ Permanent monitoring of the relevant gas condition parameters in closed tanks ■ For indoor and outdoor SF6-insulated equipment ■ Density measurement of alternative gases in electrical equipment or in the laboratory ■ General pressure and temperature measurement of non-corrosive media, e.g. transformer oil, in power transmission applications ■ High-accuracy sensor technology ■ Wireless LoRaWAN® output signal ■ Long battery life ■ Good long-term stability and EMC characteristics In order to prevent system failures in switchgear and network outages, the permanent monitoring of the gas density is essential. The model GD-20-W calculates the current gas density from the pressure and temperature using a complex virial equation in the gas density sensor’s powerful microprocessor. Pressure changes resulting from temperature effects will be compensated by this and will not affect the output value. Due to its high long-term stability, the sensor is maintenance-free and requires no calibration. Due to the hermetically sealed weld seam and a measuring cell design without sealing elements, the permanent sealing of the measuring cell is ensured. This gas density sensor requires no external power supply due to an integrated, easily replaceable battery. By means of the integrated antenna, the sensor reliably transmits the measured values based on the LoRaWAN® protocol even over long distances. The independent sensor enables a variety of alarm settings, including alarms at low densities or high temperatures. By setting the measuring frequency higher than the transmission frequency, the sensor can immediately send a warning when a threshold value is reached and does not need to wait for the next scheduled transmission. If no threshold value warning is triggered, only the last measured values are transmitted in the next transmission period to save energy and bandwidth. WIKA data sheet SP 60.78 • 07/2025 Data sheets showing similar products: Transmitter for density, temperature, (...) of insulating gases with Modbus® output; model GDHT-20; see data sheet SP 60.14 Gas density sensor for gas density, temperature, (...) of insulating gases with Modbus® output; model GD-20; see data sheet SP 60.77

Accuracy specifications Output parameter Compensated pressure range in bar abs. [psi] at 20 °C [68 °F] (g/i SFe) ■ Compensated absolute pressure at 20 °C [68 °F] ■ Compensated gauge pressure at 20 °C [68 °F] based on 1,013 mbar [14.69 psi] ■ Battery status in percent 1) Specifications apply to measurement of the compensated pressure under reference conditions and position. Accuracy determined for pure SF6 2) At temperatures below -35 °C [-31 °F] voltage drops may occur that can lead to signal interruption. The sensor will start to perform normally again when temperatures rise above -35 °C [-31...

Thread size Process connections Standard EN 837 ■ G % B WIKA data sheet SP 60.78 • 07/2025

For approvals and certificates, see website WIKA data sheet SP 60.78 • 07/2025

WIKA data sheet SP 60.78 ∙ 07/2025

WIKA data sheet SP 60.78 • 07/2025

Beschreibung Bestellnummer Battery pack Tadiran SL860+HLC1020+KAB+STAB 14615879 O-RING 30 x 1.5 ISO3601 EPDM 70 black Minimum order quantity 100 x Model / Measuring chamber / Process connection / OptionsThe LoRa® brand and the LoRa® logo are trademarks of Semtech Corporation. LoRaWAN® is a trademark used under licence from LoRa Alliance®. © 11/2020 WIKA Alexander Wiegand SE & Co. KG, all rights reserved. The specifications given in this document represent the state of engineering at the time of publishing. We reserve the right to make modifications to the specifications and materials. WIKA data...