Industrial Automation

Protecting Against Surges: Circuitry for DIN Valve Connectors

Ryan Smith

Just a few months ago, we talked about the intense and growing demands placed on DIN valve connectors in industrial environments.


While DIN valve connectors may seem rather insignificant when compared to all the other components needed to keep your industrial application running, they play an incredibly vital role: supplying power (and sometimes signal transmission) to end devices such as solenoid valves, transducers, cylinders, and pressure switches. The primary benefit for a DIN valve connector over a traditional hard-wired device is quick installation and ease of maintenance.


In that same blog, we also discussed the three types of valve connectors you can choose from—Forms A, B and C. Once you’ve mastered these differences, it’s time to think about DIN valve connector circuitry.

Why Does Circuitry Matter?


Most of the machinery used in today’s plants depends on microprocessors and sensitive electronic equipment like computers and PLCs to automate processes.


Unpredictable power surges caused by lightning, grid switching, faulty wiring, power restoration after an outage, over-voltage from the utility, and power fluctuations in other areas of the plant can damage this sensitive equipment, which may lead to downtime and failure. Over the years, our increasing dependence on electronic equipment has also significantly boosted the need to defend against electrical surges at many different points throughout a plant.


In the case of a solenoid valve, a surge will occur while the coil de-energizes inside the solenoid. The transient wave of current can flow downstream and damage other devices and components. You can absorb the surge voltage by adding a protective circuit between the solenoid and panel devices. One economical place to consider adding a protective circuit is inside the DIN valve connector.


Two methods for adding circuitry to a DIN valve connector are soldering or a PCB. Soldering is the process of welding the protective circuits to the contacts inside the DIN valve connector. A PCB is added during the production process at the factory and offered as a finished good.


The Importance of PCBs


Made of a material that doesn’t conduct electricity, printed circuit boards (PCBs) support and provide electrical connections between components. A PCB is a more a reliable method to add circuitry to a DIN valve connector. The primary benefit is superior vibration and shock resistance thanks to the components sitting flat to the top of the board. Also, a PCB allows for a low-profile solution inside the DIN valve connector for easy assembly and access.


On a DIN valve connector, a printed circuit board offers three primary purposes:


  1. Functional indication, a visual LED indicator that lets you know when it’s running or turned on
  2. Suppression protection, stopping or redirecting surges at the connector to prevent damage
  3. Converting AC input into DC output


When selecting a circuity options, the type is heavily dependent on end-device and application requirements. Belden’s DIN valve connectors are available with a variety of circuity options to choose from:


  • LED – available as a stand option for function indication only or with protective circuits. Available for DC and AC application from 12 V to 250 V
  • Recovery diode – a simple solution to protect against dropout voltage with practically no surge voltage existing. Only available for direct current (DC) and applicable up to 250 V.
  • Suppression diodes – Fast protecting against dropout voltage. Reserve polarity safe and applicable for both AC or DC applications. Only available up to 48 V.
  • Varistor- Protection at Line-Voltage with quick reaction of induced voltage but higher response time compared to the suppressor diode. Available from 24 to 250 V AC/DC.
  • Bridge Rectifier - a full wave rectifier that allows conversion from AC input to DC output


Valve Connectors from Belden


For more than 50 years, Hirschmann and Lumberg Automation, both Belden Brands, have supported end devices like solenoid valves, pressure sensors, temperature sensors and flow monitors with a comprehensive, end-to-end product portfolio.


Our DIN valve connectors are available in a variety of styles, including field-attachables, single- and double-ended molded cordsets, adaptors, molded splitters and receptacles. They’re also available with many circuitry options to make sure your plant is protected from surges. Learn more here.


We have more to share about valve connectors, so make sure you subscribe to our blog. In the next few months, we’ll take a closer look at gaskets and gasket styles—another important consideration when selecting DIN valve connectors.