Festo has developed an electro-pneumatic valve terminal for machine
builders, called MPA, that is suitable for use with multi-pole plugs and
cables in simple stand-alone applications or in fieldbus networked
installations
Original equipment manufacturers widely favour the brick type pneumatic
valve terminal, which is made up of individual slices. It is typically
very cost effective, offers compact dimensions, high flow rates and
simple connectivity. However, special-purpose machine builders often
require a more flexible solution to cope with changing specifications
right up until final commissioning and opt for valve terminals in which
the valves simply plug into the manifold. Demand for this kind of
flexibility that has inspired Festo's new valve terminal, the MPA
Since their introduction about eight years ago, valve terminals have
changed the way electro-pneumatic machines are built and controlled.
Distributed electrical I/O and solenoid valve manifolds are now the
accepted norm. Bringing the two together is the best way to reduce
component and implementation costs, according to Festo, but how can this
cut the cost of components? Festo's Jacqui Reid explains.
Using a single node for the electrical and pneumatic modules can cut the
cost of control for a typical machine station by 25%. The number of
fieldbus nodes is halved, reducing purchase costs, wiring time and the
time it takes to set-up and configure fieldbus nodes. It is also a lot
easier to run the connections from individual actuators back to a common
point - it's faster and a lot easier to logically fault find.
We have also worked hard to ensure that users of the new valve terminal
will be able to take full advantage of the flexibility of the system.
Easy to access user software allows the configuration of a complete
terminal from a menu driven program accessible to all users via the
Internet. The unit is then delivered to the customer pre-built and ready
to install .
Any number of valve positions from four to 32 can be accommodated by the
MPA, and up to 128 electrical I/O can be flexibly configured on the same
manifold. When it comes to selecting which fieldbus to use the choice is
wide, including DeviceNet, Profibus DP, InterBus, CANopen and CC-Link.
Fieldbus is still not as broadly used on automation machinery in the UK
as it is in most other parts of Europe. Possibly, this reluctance is due
to the costs incurred as the end-users train their maintenance teams to
become familiar with new software. One of the key features of this new
valve terminal is a completely new approach to diagnostics. Fault finding
and error diagnostics are given the highest priority on the MPA system.
Integral LEDs, a simple low-cost hand held interface and powerful
fieldbus accessible features combine to make this one of the fastest and
easiest systems to install and commission.