A Look at Various Types of Industrial Transmitters – Part II

In the preceding post, we had mentioned that transmitters are divided into three groups – type, signal production, and process instrumentation. We had also provided details of pneumatic and electronic transmitters, and its subtypes. In this post, we shall look at the transmitters, which are utilized for process instrumentation purposes.

Various Types of Process Instrumentation Transmitters

In industrial automation, industrial transmitters play a vital role in accurately converting process parameters like temperature, pressure, flow, and level into readable signals. Each transmitter type is engineered for a specific function, and understanding them is crucial for efficient process control. Below, we explore some of the most widely used different types of transmitters

• Flow Transmitter: As the name suggests, these transmitters provide measurements on the flow of liquid or fluid. This transmitter type consists of a transmitter and a flow sensor in one product. This allows it to generate an output up to 20mA. Flow transmitters are designed using different technologies, these include ultrasonic flow sensors, differential pressure flow sensors, and velocity flow sensors. These devices are widely used in water treatment plants, food & beverage industry, oil and gas operations.
• Temperature Transmitter Types: The design of temperature transmitters includes a transmitter, and a temperature sensor. The sensor sends a signal to the transmitters, which calculates the temperature, and converts it into an output signal. There are two common types of temperature transmitters:
  • Thermocouple Type: A temperature transmitter with a thermocouple sensor is capable of calculating temperature by measuring the electromotive force created by a change in process temperature.
  • RTD Type: This temperature transmitter comprises RTD sensors, which change electrical resistance due to the change in process temperature. The relationship between these two aspects is used to calculate the temperature.
• Types of Pressure Transmitter: These transmitters are used to measure pressure in different processes. Pressure transmitters are divided into three types:
  • Absolute Transmitter: This transmitter take vacuum pressure as its base, and then measures process pressure.
  • Gauge Transmitter: This type measures process pressure with the location’s atmospheric pressure as a base.
  • Differential Transmitter: When sensing units are introduced to multiple pressures as inputs, differential transmitters measure the differences between the various pressures.

Choosing the right pressure transmitter depends on process conditions like pressure range, media, and required accuracy. These industrial transmitters are prevalent in:

• Chemical plants
• HVAC systems
• Pharmaceutical manufacturing

• Types of Level Transmitter: These transmitters are designed to measure the level of a liquid of solid within an enclosed space or vessel. There are seven types of level transmitters, which include:
  • Point Level: These are designed to provide an output signal when a particular measurement level has been reached. The output signal can be an electrical signal to turn on a switch, or an audible alarm.
  • Continuous Level: This transmitter measures level within a particular range. It is also designed to provide updated measurements as the level changes.
  • Ultrasonic Level Transmitter: Ultrasonic level transmitters allow for non-contact level measurements of bulk solids, or viscous liquids.
  • Conductive Level: This type is used to measure different types of liquids at point level. Liquids can include water, caustic soda, and hydrochloric acids, and other corrosive fluids.
  • Pneumatic Level: These transmitters are ideal for applications that comprise slurry or sludge. They can be used in applications that does not have electricity.
  • Capacitance Level: This industrial transmitter type is used to provide continuous measurement of non-conductive liquids that have a high dielectric constant.
  • Hydrostatic based: As the name suggests, this transmitter relies on hydrostatic pressure to determine the level of a liquid.

Industrial Sensors vs. Industrial Transmitters

When it comes to process control and industrial automation, choosing between an industrial sensor and an industrial transmitter can make a big impact on performance and accuracy. At The Transmitter Shop, we specialize in high-quality industrial transmitters that are engineered for reliability, precision, and seamless integration into control systems.

Industrial Sensors – Detect & Respond Locally: Industrial sensors are devices that detect physical properties such as pressure, temperature, flow, or level and convert them into an electrical signal. These signals are typically unconditioned and may not be suitable for long-distance transmission.

Know the Common types of sensors:

• RTDs and Thermocouples (for detecting temperature)
• Piezoelectric sensors (for pressure)
• Ultrasonic and capacitive sensors (for level)

These sensors are often used in local control panels or where only basic detection (like on/off or threshold alarms) is required. However, they lack signal conditioning, which is essential in modern industrial environments.

Industrial Transmitters – Accuracy & Long-Distance Signal Integrity

Industrial transmitters, like those offered by The Transmitter Shop, take input from a sensor and convert it into a standardized output signal (e.g., 4-20 mA, HART, Foundation Fieldbus). This ensures accurate, noise-resistant communication to PLCs, SCADA, and DCS systems.

Transmitters are ideal for applications that require precise measurement, real-time control, and remote monitoring, especially in industries like oil & gas, power, water treatment, pharmaceuticals, and manufacturing.

When to Use Sensors vs. Transmitters

• Use industrial sensors when your application requires local control, basic threshold detection, or when integrating with a local panel.
• Use industrial transmitters for centralized monitoring, automated control, and when accuracy and signal integrity over distance are critical.

When it comes to signal production, and process instrumentation, there are a variety of industrial transmitters to choose from. With these two posts, customers will have more knowledge when enquiring about transmitters for their industrial applications.

At The Transmitter Shop, we offer a wide range of industrial transmitters backed by expert support and competitive pricing. Contact us today and find the perfect solution for your application.

Frequently Asked Questions (FAQ):

What is an industrial transmitter?

An industrial transmitter converts physical measurements like temperature, pressure, flow, or level into an electrical signal for control systems. It's vital for real-time monitoring and automation in industries like oil & gas and manufacturing.

What are the functions of an industrial transmitter?

Industrial transmitters are used to convert physical parameters such as pressure, temperature, or flow into standardized electrical signals for monitoring and control. These devices ensure accurate data transmission to process control systems across various industries.

How does an industrial transmitter work?

An industrial transmitter senses a physical variable using a sensor and then converts it into a measurable electrical signal. Different types of transmitters are designed for specific applications, ensuring precise and reliable data communication in industrial environments.

What is the standard output for an industrial transmitter?

The standard output for most industrial transmitters is a 4-20 mA current signal, which is widely used due to its resistance to electrical noise and ability to travel long distances without signal loss.