A multivariable transmitter is a type of pressure transmitter and this transmitter would calculate the flow using the differential pressure. This transmitter can measure the differential pressure, static pressure, and temperature in a process. This transmitter can be used as a mass flow transmitter, so while using this transmitter like a mass flow transmitter, we can compensate for the changes in the flow parameters such as density by using the above-mentioned independent values. We can also use a multivariable transmitter to calculate the mass flow, energy flow, volumetric flow, and totalized flow.

- What is a differential pressure flow meter and what are its types?
- What is a positive displacement flow meter and what are its types?
- What is a propeller flow meter and where is it used?
- What is a paddlewheel flow meter?
- What is a diaphragm pressure gauge?

**How a multivariable transmitter will be useful for gas flow applications**

The multivariable transmitter not only measures the differential pressure this transmitter would also measure the current static pressure and process temperature and also it will compensate for the changes this causes in your gas. Some of the multivariable transmitters would compensate for the shrinking and expansion of the pipework with different pressures. It can also provide accurate gas flow.

**What is the need for a multivariable transmitter?**

A multivariable transmitter measures more than one process variable in a single instrument. This transmitter can measure pressure, differential pressure, and temperature. So a multivariable transmitter can be used instead of a three single variable transmitter. A multivariable transmitter will be very useful for mass flow measurement or flow computing. This transmitter would display the electronic, and process temperature. It would also display the mass a volume flow rate.

**How multivariable flow transmitter work?**

The multivariable transmitter operates with the help of a microprocessor and this would provide better reliability and accuracy. This transmitter would be composed of sensors that will be capable to measure the differential and absolute pressure. A multivariable transmitter has many sensors so that it can measure more than one process variable. These sensors would be inside in a capsule and this capsule will be piezo-resistive. The process pressure will be applied to the transmitter diaphragm and it would be transferred to the sensor, the microprocessor combined with this sensor does all the calculations.

This transmitter can replace three transmitters, so a multivariable transmitter can reduce the installation cost. The DP transmitter is capable to measure the difference between two points in a process. Certain DP transmitters can measure the line pressure in gauge or absolute terms, the DP transmitter can also monitor the changing condition and can do sophisticated calculations in real-time. The values of these calculations will be given to PLC, DCS< or to the flow computer.

**How a DP flowmeter can improve the process performance?**

By using a multivariable DP flowmeter we can improve the process performance. So the DP flowmeter can measure more than the basic flow measurements and this would increase the precision and it would decrease the cost. The DP flowmeter can measure any type of fluid such as liquid, gas, and steam. It can be easily installed, The accuracy of this type of flow meter is really good.

**How to select a multivariable transmitter?**

- We must consider the operating temperature
- Maximum allowable working pressure
- We must also consider the supply voltage, current, and load resistance
- Turndown ratio
- Accuracy

**What are the advantages of a multivariable transmitter?**

- It can calculate the compensated flow
- It can replace three single variable transmitter
- High reliability
- The installation cost of this transmitter is very less
- Low maintenance

**What are the applications of a multivariable transmitter**?

- Custody transfer
- Energy and material balance
- Advanced control and optimization