Emerson Releases Fisher FIELDVUE 4400 Digital Position Transmitters

Emerson has expanded the Fisher FIELDVUE line of products with the addition of the FIELDVUE 4400 digital position transmitter. This device is attached to a valve so the valve position can be reported in real-time. 

 

The FIELDVUE 4400 valve position transmitter (green) installed on a valve. Image used courtesy of Emerson

 

Position Transmitters vs Limit Switches

Determining valve position is crucial to characterize operation and provide feedback for operators and control loops. Safe plant operation relies on knowing a valve’s position, particularly isolation valves that stop the flow of liquids in process equipment. For example, before starting preventive maintenance to a reactor, one of the first steps might be to shut off all inlet streams with isolation valves. The operator must know the position of these valves before the next maintenance step can begin.

Traditionally, limit switches have been the primary means of determining valve position. As the valve opens or closes, it activates a small mechanical switch that verifies whether the valve is properly seated or not. However, limit switches only report two positions, open and closed. Furthermore, they can get clogged with debris, wear out, and fall susceptible to several other adverse operating conditions that could lead to failure.

Unlike limit switches, position transmitters monitor the valve's stem, giving operators real-time data on the position of the valve. This type of feedback can be used to determine if the valve is accumulating particulates and not seating properly. Additionally, instead of a simple open or closed indication, operators can see how far open or closed a valve is at any time.

 

The Fisher FIELDVUE 4400 position transmitter relays uninterrupted valve position information. Image used courtesy of Emerson

 

Emerson’s Fisher FIELDVUE 4400

The Fisher FIELDVUE 4400 valve position transmitter is designed to work in a variety of industries, though specifically, it targets shutdown operations for steam, inlet streams to reactors, and other necessary isolation operations. 

Rather than a binary "on" or "off," the FIELDVUE 4400 reports a standard, analog 4-20 mA signal that scales linearly with the valve position. Therefore, if the valve does not seat properly on closing, it will perhaps report 4.2 mA, which may be close enough to fool a limit switch but is open enough to let the operator know there is a problem.

The FIELDVUE 4400 position transmitter still has two limit switches for a secondary look at ensuring proper opening and closing, but the 4-20 mA signal yields valuable troubleshooting data. As such, it can be integrated into many existing valve systems that already use limit switches. Besides the position data, the sensor also reports diagnostics to ensure all systems work as expected.

 

The FIELDVUE 4400 position transmitter is designed to deliver greater reliability than limit switches in valve applications. Image used courtesy of Canva

 

Reliable Position Indication

The Emerson Fisher FIELDVUE 4400 digital position transmitter will ultimately help with troubleshooting efforts in various industries. Plenty of times, a valve becomes stuck, and operators do not realize it. With the FIELDVUE 4400, the position is known at all times, not just during switching operations. For troubleshooting equipment and lines, the FIELDVUE 4400 will help prove if a system is innocent or guilty of process excursions.