The PVC4001 configuration combines a MEMS thermal conduction sensor, measurement electronics, a microprocessor, and an onboard barometric pressure sensor. This is within an ultra-compact PCB assembly with a connector-terminated wire harness, said the San Jose company.
The device is aimed at portable digital vacuum gauges and for leak detection in closed systems maintained under primary vacuum, including vacuum-insulated panels.
Posifa writes:
“Based on Posifa’s second-generation MEMS thermal conduction chip, the PVC4001-C operates on the principle that the thermal conductivity of gases is proportional to vacuum pressure. Its electronics and microprocessor amplify and digitize the sensor signal and provide output via an I²C interface. For applications requiring calibrated output, users can enter up to 10 pairs of calibration points, which are used by a built-in piecewise linearization algorithm.”
To minimize drift due to sensor self-heating, the microprocessor uses a pulsed excitation scheme. This sees the sensor heated for about 100 ms and then turned off for one second.
With an operating temperature range of -25 °C to +85 °C, the device provides a measurement range from 0.001 Torr to 900 Torr (1.3*10-4 kPa to 120 kPa). This is with a response time of less than 200ms.
Because Pirani vacuum sensors typically lose resolution above 10 Torr, says Posifa, the PVC4001-C adds the onboard barometric pressure sensor. This supports measurement from 10 Torr to 760 Torr with 5% accuracy across that extended range.
Samples and production quantities of the PVC4001-C are currently available.
You can read more information about the MEMS Pirani vacuum transducer on the Posifa Technologies website, including the datasheet (PDF).
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