compact programmable safety controllers offer an alternative to hard-wired
systems and safety PLCs for systems as small as two to three safety devices. The
new G9SP controllers from Omron Scientific
Technologies Inc. also provide a software-based solution that can be
quickly programmed to satisfy the complex safety control needs of small and
"We offer a higher end safety PLC but have
never had a safety controller in this small form factor," says Tony Rigoni, business
development manager for Omron STI. "Competitive products are basically
configurable relays, and the G9SP is different because of its software
capabilities. With a configurable relay, the user can access a block of I/O and
configure the outputs to create basic logic but there is no programmable logic
in the system."
"Software differentiates our system
because you can use OR logic, NOR logic, counters and timers to provide logical
functions found in higher end safety PLCs, but in a smaller size and with less
available I/O," Rigoni says.
G9SP programmable safety controllers are
targeting applications in packaging, food and beverage, automotive component,
injection molding, and printing where customer-driven machine set-up changes
demand equally flexible safety solutions. The controllers can also seamlessly
connect to an Omron PLC using the FINS protocol.
The G9SP controllers deliver
diagnostics and monitoring via Ethernet or a serial connection, and support
direct connection with non-contact switches and safety mats. Three base models
offer a range of I/O, and four types of expansion I/O units are available for
hard-wired diagnosis or standard signals. List prices start at under $600.
"With the G9SP's programming
software, users can easily design, verify, standardize and reuse safety
control," says Rigoni. "And because the G9SP isn't hardwired into the control
system, users will benefit from previously unavailable levels of safety system
flexibility by quickly and easily reconfiguring the units when new safety
features are added to their set-up."
In the past, the traditional approach has
been to hard-wire safety devices such as light curtains or e-stop switches
directly to a safety relay in a one-to-one connection. †In many control cabinets, there would be 10 to
20 safety relays that normally used a hard-wired type of logic. One relay would
be wired to combine an AND signal with another relay, so an e-stop or light
curtain could shut down the machine.
Rigoni says the systems were troublesome and,
if you looked at industry statistics, it cost anywhere from $40 to $60 to wire
each point. On the high end, companies have moved to safety PLCs that generally
cost anywhere from $2,000 to 5,000. But to justify the cost of a safety PLC,
the system needs to have 20 to30 safety I/O components and systems are normally
installed by end users on larger lines in a factory.
"There has been a void in the
marketplace for a product that fits the need for a compact programmable safety
controller," says Rigoni. "The target is systems with at least two to three
safety devices because, if there is only one safety device, it is less
expensive to run it to a relay."
Using this type of device, all of
the I/O is basically fixed. The OEM wires a light curtain or e-stop interlocks
directly into the controller and everything is controlled via software. Using a
simple function block diagram, the user can drag and drop a safety mat and
e-stop into the diagram to "wire" them together.
The user can add logic to the system
using constructions such as AND, OR and utilize timers, up and down counters and
pulse generators. Users can also implement serial to parallel conversions and a
button or rotary dial to switch programs.
From the standpoint of the machine builder, the
solution provides a high level of flexibility. Many OEMs have core machines with
options that would require adding a safety relay and re-wiring it into the
machine. †What the OEM can do now is dedicate
I/O for each option, and switch the program to enable that option.
"Most OEMs implement limited safety
solutions primarily as an option, so our business has been focused on end users
and compliance with safety regulations," says Rigoni. "This product provides a
solution for OEMs that gives them more responsibility. †And with more global standards, OEMs in the
U.S. will need to become more safety conscious and add more safety features to