Know How to Zero Absolute Pressure Transmitters and Sensors

Pressure transmitters and sensors are used in various industrial applications for measuring the absolute, gauge, and differential pressures of fluids. High accuracy is one of the important requirements in many processes, as their safety and outcomes are dependent on them. The pressure transmitters and sensors are often adjusted to zero point for use in applications where the highest level of accuracy is needed. Although zeroing an absolute pressure transmitter and sensor may seem easy, it is not always so. There are several challenges involved. This post offers insights on how to zero absolute pressure transmitter and sensor and several challenges involved.

Challenges Involved in Zeroing an Absolute Pressure Transmitter

Absolute zero point is achieved through calibration. Here, zero-point means setting the pressure transmitter to absolute vacuum or 0 bar absolute. Zeroing an absolute pressure transmitter and sensor can be problematic due to the following reasons.

Achieving a complete or zero vacuum through absolute pressure is quite difficult.

Maintaining a pressure equilibrium in a closed system on achieving absolute zero can be difficult.

The zero point signal may shift on installation due to mounting position or any other mechanical strain on the pressure transmitter. Thus, it must be calibrated carefully.

Absolute zero point of a transmitter may shift during the operation on exposure to high temperature or due to continuous aging.

Tips on How to Zero Absolute Pressure Transmitter and Sensor

There are several proven ways to zeroing an absolute transmitter and sensor. The following are a few common ones among them.

The absolute pressure sensors are connected to powerful vacuum sources and pumped for several hours. The pressure adjustment of the sensor is checked using a thermocouple vacuum gauge. Due to the concerns about the accuracy of thermocouple vacuum gauges, nowadays they are being replaced with capacitance vacuum transducers. Generally, diaphragm-type transducers are chosen for the purpose because they assure improved accuracy and resolution.

The absolute pressure transmitter is zeroed using a piston gauge. This technique is usually preferred over the first technique of thermocouple vacuum gauge because the pressure differentials across the test system remain unique and steady during the testing. If the Device under Testing (DUT) is linear, then there is a very small chance of error from this type of testing.

The absolute pressure transmitter can be zeroed using a barometer. This technique is considered the simplest of all. It requires the simplest test setup and needs no vacuum pumps. Like the above technique, if the DUT is linear, there will be a trivial potential error from this technique.

If you wish to calibrate the absolute pressure transmitter and sensor to zero point, it is important to seek the services of experienced calibration services. The Transmitter Shop (TTS) provides specialized calibration services for different types of transmitters including pressure, temperature, gauge, and differential pressure transmitters.

The Transmitter Shop (Tts) are experienced professionals who can support or fulfill your Instrumentation needs. From our beginning over 30 years ago, the company has a history of providing what you need, when you need it, at reasonable prices.