Understanding the 2 Wire Transmitter Wiring Diagram: A Comprehensive Guide

A 2 Wire Transmitter Wiring Diagram is an essential piece of information for anyone working with industrial instrumentation and control systems. It illustrates how a two-wire transmitter, a common device for measuring physical parameters like temperature, pressure, or flow, is connected to a power source and a receiving instrument. Understanding this diagram is crucial for proper installation, troubleshooting, and ensuring the accurate and reliable operation of your systems. This guide will break down the fundamentals of a 2 Wire Transmitter Wiring Diagram.

What is a 2 Wire Transmitter Wiring Diagram and How is it Used?

A 2 Wire Transmitter Wiring Diagram shows a simplified circuit where the transmitter uses the same two wires to both receive power and transmit its measurement signal. This elegant design minimizes wiring complexity and cost, making it a popular choice in many industrial applications. The transmitter takes a physical input (e.g., pressure) and converts it into an electrical signal, typically a 4-20 mA current loop, which is then sent back through these same two wires to a controller, display, or data acquisition system.

The core principle behind a 2 Wire Transmitter Wiring Diagram is the current loop. Here's a breakdown of its components and function:

• Power Supply: This provides the necessary voltage to operate the transmitter.
• Transmitter: The device that measures the physical parameter and converts it into a current signal.
• Receiving Instrument: This can be a PLC (Programmable Logic Controller), a DCS (Distributed Control System), a simple indicator, or a recorder that interprets the current signal.
• Wiring: The two wires connecting all these components, carrying both power and the signal.

The importance of a correct 2 Wire Transmitter Wiring Diagram cannot be overstated; it ensures proper functionality and prevents potential damage to equipment.

Here's a look at how the current loop functions:

1. The power supply pushes a small amount of current through the loop.
2. As the measured parameter changes, the transmitter adjusts the current flowing through the loop within a predefined range (e.g., 4 mA for the minimum reading, 20 mA for the maximum).
3. The receiving instrument measures this current and translates it back into the original physical parameter.

This configuration is highly reliable because the current signal is less susceptible to electrical noise and voltage drops over long distances compared to voltage signals. It also simplifies installation, as only two wires are needed instead of separate power and signal wires.

For a clearer understanding, consider this simplified table representing a typical 2 Wire Transmitter Wiring Diagram:

If you're looking for the most accurate and detailed visual representation to help you connect your two-wire transmitter correctly, refer to the specific 2 Wire Transmitter Wiring Diagram provided by the manufacturer of your instrument. This will ensure you have all the necessary information for a successful installation and operation.