Valve-Net is the name of a new control unit for valves, which makes intelligently distributed control possible via coupling to a fieldbus. With the launch of the Valve-Net system, Invensys is offering a significant improvement in valve control.
Cut cabling costs
Valve-Net makes it possible to connect a group of valves by means of one single shared cable, which reduces installation cost, saves cable and cable trays and greatly simplifies electrical engineering and documentation. Furthermore, employing the Valve-Net system greatly facilitates possible extensions or changes in plant layout at a later stage.
Valve-Net provides for diagnostic at a glance by means of four LED indicators to display valve status:
* Indication for activation.
* Indication of open/close position.
* Operation diagnostics.
A series of unique intelligent functions to the concept of valve control. Special functions provide useful information that can help make maintenance and operation more cost effective:
Extended valve information
* Error and OK-status, with built-in maximum shift times.
* Monitoring of solenoid valve power consumption.
* Registration of supply voltage.
* Optional activation of preprogramme pulsation in connection with CIP.
Maintenance information includes the number of activations, a count of the errors - and the time of installation. Consequently, the improved information standard, in combination with the built-in self-diagnostics and preventive maintenance functions, are geared to minimise plant downtime.
Open and compatible system
Valve-Net is based on Profibus, an acknowledged international standard in fieldbus systems which will soon be included in the European standard for fieldbus (EN 50170). This means Valve-Net units can be linked up with most leading PLC-brands. Full compatibility was the major concern in the development of the system. This compatibility makes Valve-Net a good option for the extension or re-arranging of existing installations.
The electronic unit is designed to withstand the tough conditions of the process industry. Priority was attributed to obtaining total resistance to water, damp, vibrations and electromagnetic noise. Plugs are 100% waterproof and fixed lengths of ready-to-use cable are provided to eliminate installation errors and corrosion risk.
All data are stored in a flash module in the Valve-Net unit. The flash technology entails full preservation of internal memory without external power supply or battery. In practise, this means that all data will still be stored in the Valve-Net unit memory even if the unit has been disused for months or years. The design also permits the future upgrading of the software.
Distributed intelligence (prepared for the future)
The idea behind the Valve-Net concept is to place an intelligent control unit in the valve top. Distribution of control reduces the workload on the central control unit (PLC), since functions such as automatic valve activation control and counting of strokes are monitored by the Valve-Net unit.
The impact on the control system as a whole benefits:
* Reduced system load.
* Reduced programming time (simpler programs).
* General improvement of the information/service level of the entire installation.
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