Case Study: Retrofitting Water Valves for Remote Position Information

Transforming Valve Monitoring with POSITAL UCD Absolute Rotary Encoders

In the realm of municipal water management, efficient and accurate control of water flow is paramount. In the United States, one water municipality faced significant challenges with their existing valve monitoring system, which relied on contact-based proximity sensors. These sensors only provided binary information, indicating whether the valves were fully open or fully closed and were unreliable as a result of being exposed to the outdoor elements. This limitation hindered precise water flow management, prompting the municipality to seek a more advanced solution that could not only be easily integrated into new assemblies, but also retrofitted into existing valves.

The Challenge

The municipality’s existing system utilized contact-based proximity sensors to monitor the position of their control valves. While these sensors were capable of indicating when a valve was completely open or closed, they failed to deliver detailed information about intermediate valve positions. This lack of granularity in position data posed several issues:

• Limited Control: Operators were unable to fine-tune water flow, leading to inefficiencies in water distribution.
• Maintenance Challenges: Due to the binary nature of the sensors, diagnosing issues with valve positioning required manual inspection, increasing maintenance costs and downtime.
• Wear and Tear: Contact-based sensors, such as potentiometers, were prone to wear over time, further compromising the reliability of the system.

The Solution

To address these shortcomings, the municipality decided to retrofit their water valves with POSITAL UCD absolute analog rotary encoders. These encoders provided a comprehensive solution with several key advantages:

Enhanced Position Data

Unlike contact-based proximity sensors, POSITAL UCD encoders offered detailed information on the specific position of the valves. This capability allowed for precise control of water flow, enabling operators to adjust valve positions with greater accuracy and respond to varying demand conditions more effectively.

Reliable and Durable Design

POSITAL UCD encoders are based on Hall-effect and TMR (Tunneling Magnetoresistance) sensing technologies. These technologies are contactless and thus not subject to wear and tear, ensuring long-term reliability. Additionally, the encoders feature a stainless steel housing and IP68/69k ratings, making them ideal for outdoor environments. Some encoders have demonstrated remarkable durability, continuing to perform reliably even after a decade of service.

POSITAL UCD…G10G absolute rotary encoders feature a stainless steel housing and are available with a wide variety of electrical interfaces including analog voltage, analog current (4-20mA), CANopen, J1939, SSI, IO-Link and MODBUS RTU.

Integration with PLC Systems

The municipality integrated the POSITAL UCD encoders with their existing systems. The scalable 4-20mA output allowed for continuous remote monitoring of valve positions, providing real-time data to operators. At the customer’s request, POSITAL modified the output software to mimic that of a mechanical potentiometer, with the output continuing linearly when the shaft moved out of range. This allowed operators to be able to identify if a valve had moved outside of its pre-defined range, and if so, if it was by a large enough angle to be of concern.

As the Valve Position Indicator (vertical silver rod) rises and falls its position is determined by converting the shaft position of the rotary encoder (right) into a linear measurement.
Note: Mounting bracket not shown

Implementation and Results

The implementation of POSITAL UCD encoders involved several steps:

• Assessment: The municipality conducted a thorough assessment of their existing valve infrastructure and identified the specific requirements for retrofitting.
• Installation: The encoders were installed on the control valves, replacing the contact-based proximity sensors. The installation process was straightforward, only requiring the customer to fabricate a simple ‘L’ bracket to hold the encoder. No modifications to the valve were necessary and the valve could even be in service when the upgrade was performed.
• Integration: The encoders were integrated with the PLC system, enabling seamless communication and data transfer.
• Testing: Extensive testing was conducted to ensure the accuracy and reliability of the new system. The municipality monitored the performance of the encoders and worked with Everight Position and POSITAL to make necessary adjustments to optimize their operation.

The results of the retrofit were overwhelmingly positive:

• Improved Control: Operators gained precise control over valve positions, allowing for more efficient water distribution and management.
• Reduced Maintenance Costs: The durability and reliability of the POSITAL UCD encoders minimized the need for frequent maintenance, resulting in cost savings.
• Enhanced Monitoring: Real-time data from the encoders enabled proactive monitoring and quicker response to potential issues, reducing downtime and ensuring continuous operation.

Conclusion

This case study highlights the transformative impact of retrofitting water valves with POSITAL UCD absolute rotary encoders by a US water municipality. By moving away from contact-based proximity sensors and embracing advanced sensing technologies, the municipality achieved significant improvements in control, reliability, and operational efficiency. The success of this retrofit serves as a testament to the importance of adopting innovative solutions in municipal water management, paving the way for more sustainable and effective infrastructure systems.