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It is absolutely essential that the regulations stated in EN 574 : 2008 are complied with
for assemblies involving the installation and commissioning of
safecap
A + B !
SAFETy RULES AND REGULATIONS
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Definition – Dual Control
Dual control systems require simultaneous operation using both
hands in order to start or maintain the operation of a machine as
long as there are any risks involved. They must be positioned
outside the danger area so that the operator cannot enter this area
before the machine has been completely switched off.
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Avoiding inadvertent operation and overruling
(see also EN 574 section 8)
The
safecap
of a dual control have to be arranged according to
the risk evaluation made for every single application so that the
protective effect of the dual control cannot be overruled easily and
the possibility of inadvertent operation is kept to a minimum.
The use of only one hand, possible combinations of one hand and/
or other parts of the body and /or the use of simple aids which
might make avoidance possible are to be taken into account in
order to prevent any person from entering the danger area during a
hazardous situation. Inadvertent operation (e. g. through clothing
of the operators) has also to be taken into consideration.
Safecap
A + B have to be separated by partition walls which are arranged in
relationship to the operating side or rear side in such a way that the
safecap
cannot be operated from the operating side with the help
of the tip of a cone, i. e. the elbow. Open fitting (without operating
panel and without
safecap
protector) of
safecap
A + B is to be avoi-
ded in order to prevent the start of operation through falling items.
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Case – Fitting of safecap
(see also EN 574 section 9.3)
Case and fittings have to be assembled in such a way that they can
withstand the expected operating strain.
Selection, assembly and fitting of safecap
(see also EN 574 section 9.4)
The
safecap
have to be fitted in such a way that they can be
operated without causing fatigue (e. g. as a result of awkward po-
sitioning or inadequate movements) Inadvertent starting of mobile
and portable machines (see also EN 574 section 9.6) The design
of a dual control system must prevent inadvertent operation due
to normal handling of mobile and/or portable machines that are
controlled by it.
Mobile dual control systems
The
safecap
of a dual control system and its case must be stable
during normal use.
Mobile dual control systems have to be fitted with appliances that
prevent a change of position during operation.
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Safety Distance
(see also EN 574 section 9.8)
The safety distance between the
safecap
and the
danger area has to be determined with the time in mind that it
would take for the hazardous movement to come to a stop before
the operator can reach the danger area after releasing the.
The safety distance „S“ in mm is calculated using the following
formula: S = Vx T +C
V = touch velocity = 1600mm/s
T = slowing down period in seconds
C = additional value = 250mm
If the intrusion into the danger area during the
operating time of the
safecap
is successfully
prevented, e.g. using a safety cover for the
safecap
the value
0 can be put for C. However, a minimum
safety distance of 100 mm is to be applied at alltimes.
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Notes on Installation
The PNOZ s6 relay must only be connected as shown in the
examples for applications. Series parallel connection or series
connection of safecap relay contacts will eliminate the secure
operation of the devices. The secondary contactor or relay needs
to be fitted with guide contacts and needs to be monitored in the
feedback circuit.
To initiate a hazardous movement, two sensors
safecap
A and
safecap
B will have to be used. An output signal will be given
if both sensors are touched within a time period that is shorter
or equal 0.5 s. The sensors have to be of a kind and have to be
arranged in a way that makes it difficult to render them ineffective
or use them inadvertently.
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The distance between the sensors can be reduced by fitting one or
more partitions which are designed in such a way that the sensors
cannot be reached with the ends of a 260-mm piece of string
which represents the span of a hand. The arrangement of sensors
on a horizontal or nearly horizontal plane must be at least 1100
mm above floor level or access level.
This distance does not need to be kept if suitable safety measures
(e.g.
safecap
protector) are taken to prevent any other bodypart
(e.g. knee, hip) in conjunction with a hand from actuating the
equipment.
