Safety relay range has the spectrum covered

A Pilz Automation Technology product story

Edited by the Engineeringtalk editorial team Dec 24, 2003

A new range of microprocessor-based electronic safety relay devices covers a broad spectrum of applications from Category 2 up to and including Category 4 in accordance with BS EN954-1.

Following the successful launch of the world's first microprocessor-based electronic safety relay device, the PNOZ e1p, Pilz Automation Technology is now releasing a wide range of similar devices to cover a broad spectrum of applications from Category 2 up to and including Category 4 in accordance with BS EN954-1.

A particularly useful feature is the ability to link two relays together to perform logic "and" or "or" functions.

Each device in the innovative PNOZelog range combines the benefits of the classic electromechanical PNOZ safety relay with those resulting from modern electronic design: compact dimensions (all are just 22.5mm wide), low power consumption, long service life, resistance to vibration and increased diagnostic capabilities.

Logistic and inventory costs are reduced and product selection is also simplified thanks to the multifunctional nature of the PNOZelog units.

Dual diverse, redundant microprocessors provide improved fault monitoring on input and output circuits, which includes the detection of short circuits and line and earth faults on input wiring, as well as the detection of line and earth faults on the two semiconductor fail-safe output circuits.

LED indication on the front of the safety relays provides diagnostic information on the status of the inputs and outputs and details of the detected fault conditions.

Alternatively, PLC drivers are available on a CD-ROM to enable the diagnostic data to be relayed to a PLC and, hence, to an operator display.

Whereas the PNOZ e1p is suitable for monitoring emergency stop circuits, guard interlocks and light curtains with or without semiconductor outputs, the PNOZ e1.1p can additionally be used in conjunction with other PNOZelog devices to perform logic functions.

A further model, the PNOZ e1vp, is similar to the e1.1p but with a user-settable timer for the safe shutdown of plant and machinery.

Two versions are available, offering time delays from 0 to 10s in nine steps, or 0 to 300s in nine steps.

Other products in the PNOZelog range include the PNOZ e3.1p for use with the Pilz PSEN sensors or other safety switches with normally open and normally closed contacts; the PNOZ e3vp is similar but with the addition of a timer function as per the PNOZ e1vp described above.

For machinery that uses a two-handed start, the PNOZ e2.1p is available for use in BS EN574 Type IIIC (high integrity) applications, and the PNOZ e2.2p is for BS EN574 Type IIIA (lower integrity) applications.

If safety mats are used on applications up to Category 3, the new PNOZ e4.1p and PNOZ e4vp are available.

Both can be configured for automatic or monitored reset, but the second unit also has an adjustable time delay of up to 10s.

In order to conform with the Machinery Directive, a safety mat used on machinery must meet the requirements of BS EN1760-1:1997 (Safety of machinery - Pressure sensitive protective devices - Part 1: General principles for the design and testing of pressure sensitive mats and pressure sensitive floors).

This standard introduces the principle that a safety mat system consists of the switching mat (the input device) and the control unit (the relay) - and that joint approval is required.

Pilz has worked with Mayser so that the new Pilz relays are approved for use with Mayser SM/BK type safety mats.

Another exciting development in the Pilz range of electronic safety relays is the PNOZ e5.11p and PNOZ e5.13p dual-function relays.

The first of these can be used to monitor both an emergency stop circuit and a safety gate, while the second is specially developed to monitor an emergency stop circuit and a gate protected by the Pilz PSEN noncontact gate switches.

Using one of these devices will halve the space required in comparison with utilising separate relays.

Suitable for applications up to Category 3, the devices can be configured for automatic, manual or joint manual reset.

Compared with traditional electromechanical safety relays, all the PNOZelog devices can save a considerable amount of wiring, especially when logic and or or functions are being implemented.

During commissioning, the diagnostic capabilities - either using the LEDs or remotely via a PLC - can save extra time.