ifm efector offers a line of safety products that are designed to monitor critical safety applications
including high-speed door monitoring, escalator detection, lift position, machine part presence, and
the travel range of robots and robotic arms.
An inductive sensor made safe
ifm has manufactured the first standard inductive proximity sensor that is approved for safety
applications.
Many products designed to solve safety applications are two-piece units that are subject to misalignment
and physical damage, especially in shock and vibration environments. ifm’s new fail-safe
inductive sensor does not require a coded magnet or keyed target for safe operation. The wearfree,
one-piece solution integrates ifm’s patented, non-contact inductive sensing principle that is
now rated up to Category 4 according to EN954-1 for safety applications.
ifm’s fail-safe sensor can detect any standard metal target such as stainless or mild steel. The sensor’s
extended sensing range provides a high tolerance to misalignment and nuisance tripping in
shock and vibration environments.
Window-technology is the key to safe operation
The sensor uses ifm’s “window technology” that continuously detects a target within its enable
zone – or window. If the target moves outside its enable zone, the sensor will fail to safe. The
window technology also compensates for conventional approach angles and closing door angles.
The sensor can be connected to any standard safety relay or safety PLC including ifm’s new
multi-function safety relay.
A relay that connects standard safety devices and reduces stock levels
ifm’s multi-function safety relay is compatible with industry standard safety devices that include
e-stops, light curtains, protective guards, two-hand controls and safety sensors. The versatile,
all-in-one safety relay eliminates the need for multiple product-specific relays and reduces relay
stock levels. The compact housing is only 22.5 mm, providing up to 50% space savings in a control
cabinet. ifm’s safety relay is certified to IEC 61508, EN 954-1, EN 574 type IIIC.
Implementing a safety system using safety approved products not only increases the protection of
plant personnel, but also lowers the costs associated with downtime.
Approvals that Define Machine Safety
The US Government specifies that safety products must be proven reliable before being placed
on the market, compelling many manufacturers and installers to have their products tested by
a Nationally Recognized Test Laboratory (NRTL) in the US. Following are several standards that
define machine safety.
EN954-1 Standard - Category 4
The EN 954-1 Standard relates to the safety of machinery, safety related parts of control
systems and to general principles for design. the standard was developed by the European
Committee for Standardization (CEN).
Categories that define the behavior of the safety related parts of the control system are B, 1,
2, 3 and 4 with category B being the lowest with no special measures for safety, and
Category 4 being the highest where faults shall not lead to loss of safety and the single fault
will be detected.
IEC 61508 Standard - SIL 3
IEC 61508 Standard is defined by functional safety of electrical/ electronic/programmable
safety-related systems. This standard was developed by the International Electrotechnical
Commission (IEC). Human safety is the main focus of the IEC 61508 standard. It aims to
protect human life through analysis of the functionality of products, machinery, and equipment
that can affect human safety.
The SIL (Safety Integrity Level) is a measure of the probability of failure on demand. The higher
the SIL number the less chance it has of failing, e.g., a SIL3 device has a lesser chance of failure
than a SIL2 device.
TÜV Approval
TÜV is an independent product-safety testing and certification organization. The Organizational
Safety and Health Administration (OSHA) has approved TÜV as an NRTL. ifm’s safety
products have been tested and approved by TÜV for customers in North America.
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