Tech Briefs Magazine - October 2021 - MD-4

times to as little as five milliseconds. As a
result, equipment manufacturers can
make machine movements much more
dynamic to improve productivity without
sacrificing safety. At the same time, the
distance between people and machines
can be reduced without hazards. This
saves floor space and fulfills another end
user requirement.
In addition, since more safety devices
now have bus interfaces and are conOpen
and scalable machine safety controls platforms - such as the Rexroth ctrlX SAFETY system including
the drive-based SafeMotion software solution running on the ctrlX DRIVE (left) - and the compact SafeLogic
controller (right) give machine builders a broad range of options.
safety drive and control device suppliers:
CIP Safety on Sercos, Failsafe over
EtherCAT®
, PROFIsafe on PROFINET,
and CIP Safety over EtherNet/IP™.
Use of these high-speed safety networks,
which operate as a standalone
layer apart from the main automation
bus, has increased as more safety devices
are being tied directly to them, rather
than being separately hardwired via I/O
directly to machine controllers.
These high-speed networks also support
faster response times for safety
drives and controls. This is necessary
because drive technology has advanced
considerably. In addition, today's linear
and servo motors are engineered to
operate with much faster cycle times
than in the past.
Therefore, to ensure safety within
much shorter actuation trigger times,
machine designers must either reduce
automation sequence speeds or protect
people by ensuring a greater safety clearance
from machine movements. For
example, safety equipment such as light
curtains is installed further away from
the process, which means the machines
take up more floor space. However,
users are demanding not only safe but
also smaller machine footprints.
Leading drive and control suppliers
are responding to these trends with safety
technology capable of reducing reaction
nected via a high-speed intelligent safety
bus, diagnostics and predictive maintenance
are improved. By being on the
network, it's much easier to identify if a
device is malfunctioning, rather than
having to troubleshoot a network of
interconnected devices.
The latest generation of safety drives and controls offers significantly improved response times, intuitive graphical
programming that allows more efficient engineering, and expanded libraries of monitored safety functions
such as Safe Limited Direction that make it easier to tailor solutions to meet specific requirements.
4
Cov
ToC
Choosing Safety Platforms
The wide range of safety control platforms
available today presents a challenge
for both automation OEMs and end
users. Most automation system providers
can state that they comply (to one degree
or another) with industry standards for
machine safety devices; the differences
that need to be assessed are how those
platforms are designed to provide ma -
chine builders and end users with more
flexibility in the context of their machine
designs to maximize safety, automation
efficiency, and machine costs.
It's important to consider innovative
safety platforms that are engineered for
scalability, providing machine builders
with options to suit specific machine
requirements. These platforms start with
drive-based safety technology that does
not necessarily require the cost and complexity
of a more complex PLC-based
solution but that can still be scaled up to a
complete safety control system while staying
within the same family of products.
In addition, be sure to assess the features
and functionality of drive-integrated
safety systems. While some might
offer only five or six safety functions,
more robust solutions will offer a full
menu of 20 to 25 functions, all of which
are easily programmable using graphical
interfaces that do not require specialized
programming skills. This provides
important flexibility: if a specific section
of a machine needs a safety function
such as Safe Torque Off (STO) with
quick reaction time onboard, a full-featured
drive platform will support it via
software selection, without additional
hardware or software required.
Motion Design, October 2021

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Tech Briefs Magazine - October 2021

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