The new Machine Safety Directive, which came into force
this year, opens the doors for many safety and cost-saving
benefits. Paul Considine of Wieland Electric explains how to
exploit some of them

Following an extended transition
period between the old and new
Machine Safety Directives,
compliance with the new Directive is now
mandatory. While getting to grips with new
regulations is often distracting (or worse),
these regulations do offer some real benefits.

Clearly safety is the paramount concern
and one of the key benefits of the new
Directive is that it enables that safety to be
achieved more efficiently and cost-effectively
– when approached in the right way. This is
because the old EN 954-1 standard had
effectively fallen behind technological
advances; fundamentally it was too simple to
handle the programmable electronics that are
used in modern safety systems.

The standards underlying the new
Directive, however – EN ISO 13849-1 or EN
(IEC) 62061 – have been designed to
complement modern technologies and make
it easier to deploy them in safety systems.

A good example of this is programmable
safety relays, use of which is facilitated by the
new Directive, thus enabling greater
modularity to exploit the functionality of
these newer processing technologies.

Programmable safety relays also create
opportunities for cost-savings at every stage
of the process from initial system design
through to ongoing maintenance. At the
design stage, for instance, a flexible logic
editor allows the safety relays to be tested in
the software before installation begins. In
this way, any potential problems can be
spotted and designed out before work begins.

Consequently, much less time is spent in
onsite testing, reconfiguration and re-testing,
compared to dealing with stand-alone relays.

We have found that having this benefit of
foresight encourages engineers to try out
different solutions, potentially coming up
with a better solution, as the only implication
of getting it wrong is the need to undo the
error in the software.

Installation work is also simplified,
compared to working with stand-alone
relays, as programmable safety relays are
wired back to a central I/O point with no
need for feedback loops and interconnecting
terminals. There are also potential timesavings
on commissioning, as any errors are
clearly highlighted in the software and, as
with the design process, any errors made
during commissioning are easily reversed
through the software.

Once the system is up and running this
enhanced functionality extends to tracing
faults and fixing them when something goes
wrong, speeding up the process compared to
manual fault tracing and reducing downtime.

Furthermore, once the fault has been
identified it can often be rectified by inhouse
maintenance staff rather than calling
on specialist engineers at hourly rates that
reflect their expertise.

In terms of managing the system, the
software also incorporates a full reporting
structure linked to the technical file, so that
all information is recorded without manual
intervention and reports can be generated
very quickly. Feedback from users indicates
this ease of reporting has helped them to
understand their maintenance patterns in
greater depth and to utilise their resources
more effectively as a result.

It’s also worth mentioning that
programmable safety relays, once considered
an expensive option, are now very affordable so
there is no longer a price penalty in making use
of them. As a general rule of thumb, a system
using three to four stand-alone safety relays
can be replaced by a programmable system
for about the same cost. With more extensive
systems, using greater numbers of relays, it will
typically cost less to use programmable safety
relays than stand-alone relays, introducing
even more cost-savings to the equation.

When all of these features are considered
it’s clear that the new Machine Safety
Directive has the potential to be positively
beneficial for machine operators. Design and
installation of new or refurbished systems is
quicker, often with a better solution, and the
ongoing cost of ownership is reduced – all
adding up to an attractive return on
investment.