Domino D120i Blue IP, Product Manual

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INSTALLATION INSTRUCTIONS
L025317 Issue 5 July 2014 2-35
SAFETY OF THE LASER SYSTEM
The safety of a laser guarding is ensured by interlock doors which must be
equipped with interlock switches which are observed by a certified safety
relay.
The former standard EN 954 Part 1 classified the safety of machines into
five categories: B, 1, 2, 3, and 4.
According to the risk analysis of Domino Laser GmbH for laser coding
systems safety category 2 had to be reached. An eclectically single circuit
connection was sufficient for the safety doors when using the safety relay
“PNOZ-S4”.
EN 954 has been replaced by EN 13849.
Since the beginning of 2012 the risk analysis has to be done according to
the standard EN 13849. This standard distinguishes between different
performance levels: a, b, c, d, and e. A risk analysis according to this
standard leads to the result that performance level d has to be reached.
Therefore a two circuit connection is needed to the safety relay as it has
been needed for category 3.
This means that the laser system has to be connected by a double circuit
connection to double switches of the safety door. This double switch needs
to have forcibly guided contacts of the type “normally closed”.
When using this double circuit connection operation with or without cross-
wire short detection is possible.
Cross-wire short detection means that the safety relay detects a short
between the two circuits. A short may be produced by damaging an
interlock cable, e.g. by a vehicle in a factory hall.
Without cross-wire short detection performance level d is reached.
With cross-wire short detection performance level e is reached.
The functionality cross-wire short detection is activated on the Pilz safety
relay. Cross-wire short detection is switched off when using the setting “Cat
2/3”. It is active when using the setting “Cat 4”.
The setting of the category has to match the wiring at the safety relay.