Fieldbus solution for valve connection

Asco Joucomatic has introduced The Valve Connection System (VCS), which connects actuators and valves in an easy, quick and economical way.

The VCS is suitable for large installations and machines with up to 127 connectors for spool valves with two solenoid cells each and up to 254 sensor inputs can be connected with a single cable, spanning a length of up to 2.5km.

Automatic feedback of the control signals provides a high degree of data protection. With the VCS all types of valves can be connected. Spool valves can be used in the VCS individually or several can be linked together to form valve manifolds.

Fieldbus systems are used increasingly in installations and machines to connect inputs and actuators to a controller. The VCS has been designed with this in mind. The VCS interface acts as a communication centre for a PLC, a fieldbus and up to 127 VCS connectors. In a loop structure, data from the fieldbus passes through the interface and is transmitted to the valves via the VCS line. The corresponding feedback from digital inputs is transmitted over the VCS line to the interface and from there to the fieldbus system.

All valves and actuators with their VCS connectors are referred to as participants. The participants are connected to each other and to the VCS interface over a two-wire profiled VCS cable which cable which supply them with electrical current and data. Each VCS connector fitted on to a valve is clamped on to the two-wire profiled VCS cable.

When the lid of the connector is closed, the vampire-type plug automatically enables immediate contact with the wires of the VCS cable. The participant is connected. No tools are needed to fasten the lid. The VCS system eliminates the need for cable stripping or fastening.

Each VCS connector id equipped with a data repeater valid for a distance of up to 20m between two valves. In addition to technological features such as automatic cutting and vampire-type plugging, all the electronics used to extract data from the valves and to transmit input data from the sensors are integrates in the VCS connector, thus rendering it intelligent. This is due to a newly developed, economical, compact-sized ASIC electronic component at the heart of the VCS’s electronic system.

The standard version of the VCS interface includes a VCS power pack. Depending on the number of valves in the loop and its size, additional VCS power packs can be clamped directly on to the VCS cable to provide for appropriate power output and to compensate for any eventual voltage drop.

To ensure maximum transmission protection, the VCS line is structured as a loop, with the last valve in the line connected back to the VCS interface. The advantage of a loop system is the data transmitted is then fed back to the VCS interface and analysed. The output is switched only after the transmitted data and the feedback data are fully compatible. Faulty data blocks are thus detected and the transmission is repeated.

The valve actuators only operate when the transmitted data and the feedback data are verified as being the same. The loop structure provides for automatic addressing; each valve is automatically recognised by its position in the loop.

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