Flowserve Logix 520MD Series Digital Positioner
The Logix 520MD is a digital electro-pneumatic valve positioner from Flowserve that converts a 4-20 mA control signal into precise pneumatic actuator movement. It incorporates HART communication for configuration and monitoring and is intended for single-acting linear or rotary control valves in industrial process applications.
Product Overview
The positioner operates as a two-wire loop-powered device. It compares the input setpoint with valve position feedback and adjusts the output pressure accordingly. Local interface elements support basic setup and calibration, while HART enables remote access. The series is known for reliable positioning performance and has been applied across a range of process control duties. Current Flowserve offerings center on the Logix 520MD+ evolution of this platform, which builds on the original design with additional diagnostic and performance capabilities.
Technical Specifications
| Specification |
Details |
| Model Family |
Logix 520MD / 520MD+ series |
| Input |
4-20 mA with HART |
| Power Supply |
Two-wire, loop-powered |
| Actuator Action |
Single-acting |
| Mounting |
Linear and rotary compatible |
| Air Supply |
Regulated instrument air (typical range 1.5–6 bar for original; extended on later versions) |
| Key Features |
Digital control, HART communication, local calibration options |
| Performance Focus |
Accurate positioning with low air consumption characteristics |
| Hazardous Ratings |
Intrinsically Safe / Non-Incendive options (model dependent) |
Application Industry
Commonly applied in chemical, petrochemical, oil & gas, power, and manufacturing facilities for control valve automation where digital feedback and reliable positioning are needed.
Common Problems
Challenges with older analog positioners include limited diagnostics, slower setup, and less insight into actuator or valve condition. The Logix 520MD series provides digital communication and structured calibration to help mitigate these issues.
Replacement Models
For new installations or upgrades, the Logix 520MD+ is the recommended current-generation alternative that retains application compatibility while adding enhanced diagnostics, broader HART support, and improved environmental ratings.
Why Buy From Us
We focus on authentic Flowserve instrumentation and support customers with selection guidance for both aftermarket Logix 520MD needs and current 520MD+ solutions.
Stock & Delivery Time
Standard lead time is 6-8 weeks, depending on whether aftermarket or current production units are required.
RFQ Form
Submit your valve/actuator details, process conditions, preferred options, and quantity to receive an accurate quotation.
