Intellligent valve interlock system

The Sofis (Netherlocks) intelligent  valve interlock product range combines the reliable characteristics of a mechanical safety solution with new electronic features in various process applications. It allows communication and proofing and improves efficiency and safety.

The Intelligent Valve Interlock System has distinctive features:

  • It increases safety significantly by integrating operator procedures with DCS and SIS
  • It provides live step by step information, guidance and a process overview during the whole procedure
  • It makes operational sequences dynamic by integrating feedback from the DCS
    (pressure,temperature ect.) to authorize the next step.


The Intelligent Interlock System can be customized with various technologies and features, based on the following fundamental elements:

EKC (Electronic Key Cabinet)
ASLP (Actuator Switch Lock Panel)
ISI (Interlock System Information)




Sequence Control Panels

A combination of products can be integrated in cabinets or panels, creating a customized (Intelligent) Interlock System. Mechanical key interlocks are still at the basis of the safety system in the field. The extra intelligence offered by the additional electronic systems offers more insight, guidance and control.

Dynamic sequence

Apart from mechanically guaranteeing a strict adherence to procedure, Intelligent Interlocking allows other input signals, such as H2S or pressure levels, to be included in a predefined operating sequence. For instance, in pigging applications, the key to open the closure door is only released after the valves are operated in the correct sequence and the vessel pressure has reached a predefined level. Also, remotely authorizing the start of an operating sequence can easily be programmed. This way, the panel will only release the starting key after receiving an external authorization signal, for instance from the DCS or SIS.

MOV locked in sequence

The electronic controls of a MOV can be included in a Sequence Control Panel. This way, the MOV is integrated in a sequence with manually operated valves. The MOV can only be operated at the right moment. This means the MOV is locked without using traditional mechanical valve interlocks

Real time information

Sequence and valve status information on an ATEX certified screen or tablet provides clear understanding of the operating sequence. The screen visually guides operators through an operating sequence, offering them real-time information about required steps in a sequence, status of involved valves and particular valve locations.


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