Tech Briefs Magazine - December 2023 - MD-9

lar solution to an end user of PROFINET
the next. The easier it is for this machine
builder to switch from one protocol to
another the better.
Most remote I/O modules and valve
terminals that connect directly to the
Ethernet network support only one protocol,
or sometimes two in the case of
EtherNet/IP and Modbus TCP. When
switching to another protocol the machine
builder must replace each of the
I/O modules and valve terminals with a
similar device that supports the new protocol.
When using the bus interface approach,
only the bus interface must be
replaced. The remote I/O modules and
valve terminals connected to the bus interface
remain the same, without having
to be replaced.
With the bus interface approach to
system design, the remote I/O modules
and valve terminals form a single system
with the bus interface, and therefore, all
these devices come from the same manufacturer.
This does not mean, however,
that all field-level devices must also come
from the same manufacturer. On the
contrary, all digital and analog sensors
and actuators are supported in this approach,
regardless of manufacturer.
In addition to standard sensors and
actuators, IO-Link technology is an
increasingly popular option for smart
sensors and actuators, with a growing
list of manufacturers that support the
open specification. IO-Link technology
turns basic sensors and actuators into
smart sensors and actuators. To support
IO-Link technology, manufacturers of
bus interface solutions provide IO-Link
master modules that fit into the decentralized
system alongside the remote
I/O modules and valve terminals. IOLink
master modules support any thirdparty
IO-Link devices. In this way the
bus interface approach is completely
compatible with any third-party sensors
and actuators.
As described earlier, the bus interface
connects to the remote I/O modules and
valve terminals with a physical backplane
or via cables. In both cases, the highspeed
communications passing between
the bus interface, modules, and terminals
is the same. The communications are fast
with low overhead, and support auto-recognition
of all connected devices.
The bus interface automatically recognizes
all modules and terminals that are
connected to it. At power-up of the sysMotion
Design, December 2023
9
tem, the bus interface is immediately
ready to pass data between the Ethernet
network and the connected devices. The
bus interface makes the decentralized
topology of modules and terminals appear
to the PLC as a single, smart system
of inputs, outputs, and pneumatic valves.
Place I/O and Valves Where You
Need Them
Whether connected via physical backplane
or over cables, the communications
between modules and terminals are
the same. This means that machine builders
can use a mix of decentralized, individual
modules and centralized valve
manifolds with on-board I/O. This is referred
to as a hybrid approach to system
design because of the mix of centralized
and decentralized devices. Cable lengths
between distributed modules and terminals
can be up to 50 meters, allowing very
large machines with heavily decentralized
I/O and valve needs to be addressed.
The ability to mix modules and terminals
together in the system means that
machine builders can install I/O and
valves in the physical locations and orientations
that make most sense to the overall
machine design. The machine builder
has more freedom and flexibility when
placing I/O modules and valve terminals
around the machine. All modules and
terminals are IP65 and IP67 rated, which
means they can be mounted outside of
the control cabinet.
The technology that supports the bus
interface approach to decentralized,
remote I/O and valve systems has been
in development for many years and is
based on decades of experience in the
development of smart pneumatic control
and I/O systems. A bus interface
approach, such as the Festo Automation
Platform (AP), provides greater flexibility,
easier integration, lower maintenance
costs, and higher productivity for
today's machine builders.
This article was written by Eric Rice,
Product Market Manager
- Electric
Automation, Festo Corporation (Islandia,
NY). For more information, visit www.
festo.com/us/en/.
http://www.festo.com/us/en/ http://info.hotims.com/84486-704
Tech Briefs Magazine - December 2023

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