14
Operating instructions
Two-hand control panel
SEPK 02.0 / SEPG 05.3 / SEP 01.0 /
SEP 01.4 / SEPLC 05.2 / SEP 07.0 / SEP 09.0
EN
Avoiding inadvertent actuation and tampering (also refer to
EN 574)
In accordance with the risk analysis for the individual application,
the BWT of a two-hand control panel must be arranged so that the
protective function of the two-hand control panel cannot be tampered
by simple means and that the probability of any inadvertent actuation is
as low as possible. The utilisation of one hand, possible combinations
of one hand and/or other body parts and/or the use of simple tools
enabling tampering, must be accounted for in order to avoid access to
the hazardous area as long as a hazardous situation exists. Inadvertent
actuation (e.g. by the clothes of the operator) must be likely accounted
for. Partioning walls must be installed between the BWT, which are so
arranged behind the operating side and the rearside that they cannot
be actuated from the operating side by means of the top of a test cone
representing the elbow.
The arbitrary installation (without operating panel) of BWT
must be avoided, to prevent them from being triggered by
falling objects etc.
Enclosure mounting of BWT (also refer to EN 574)
The enclosure and the ixing possibilities must be designed so that they
withstand the operating the foreseeable working loads.
Selection, design and installation of BWT (also refer to EN 574)
The BWT must be so installed that they do not cause human exhausti-
on (e.g. as a result of unhandily positioning or insuitable movements).
Inadvertent starting of mobile and portable hand-held machines
(also refer to EN 574)
A two-hand control panel must be so designed that any inadvertent ac-
tuation as a result of the normal handling of the mobile and/or portable
hand-held machines, which it controls, is prevented.
Mobile two-hand control panels (also refer to EN 574)
The enclosure, in which a two-hand control panel is installed, must be
steady under normal circumstances. Mobile two-hand control panels
must be equipped with features, which prevent a relocation during the
actuation.
Safety distance (also refer to EN 574)
The safety distance between the BWT and the hazardous point must be
so large, that when the BWT is released, the hazardous point can only
be reached after the hazardous movement has come to standstill.
The safety distance "S" in mm is calculated using the following
formula:
S = V × T + C
Legend:
V
= Gripping speed = 1,600 mm/s
T
= Run-on time in seconds
C
= Additional value = 250 mm
If access to the hazardous area is safely prevented upon actuation of
the BWT, e.g. by a protective cover of the BWT, the additional value C
can be taken equal to 0. The minimum safety distance anyhow must be
100 mm.
Safety rules for BWT sensor buttons
• In constructions for the assembly and putting into operation of BWT
sensor buttons (A + B), the requirements of EN 574 must be impera-
tively observed!
• In accordance with the risk analysis for the individual application, the
BWT sensor buttons of a two-hand control panel must be arranged so
that the protective function of the two-hand control panel cannot be
tampered by simple means and that the probability of any inadvertent
actuation is as low as possible.Avoiding inadvertent actuation and
tampering (see igure).
• The arbitrary installation (without operating panel) of BWT sensor
buttons A + B must be avoided, to prevent them from being triggered
by falling objects etc.
Installation instructions: I
• The two-hand relay SRB-201ZH 24VDC must only be wired as shown
in the wiring examples. Any parallel- or series-wiring of the relay con-
tacts of the BWT sensor buttons neutralises the safe function of the
devices. The downstream contactors or relays must be equipped with
positive-guided contacts and monitored in the feedback circuit.
• To trigger a hazardous movement, two sensors "BWT-...A and BWT-
...B" must be used. An output signal is generated, when both sensors
are actuated within a timeframe smaller than or equal to 0.5 sec. The
sensors must be procured and arranged so their disabling by simple
means or inadvertent actuation is prevented.
• The use of BWT sensors in the enclosures of two-hand control panels
still is a problem at this time, as currently no deined test method
exists regarding the installation of the sensors in respect of protection
against tampering with the knees or the elbows.
• The measuring cone provided for this test, which at the time that the
standards were drafted was only aligned to control elements with
mechanical operating principle, should cause the triggering of the
sensors in case of a non-appropriate installation.
• The sensors however function capacitively in conjunction with the
human hand. A suitable material for a measuring cone, which could
inluence the sensors, is not known. The measuring cone furthermore
insuficiently takes into account that sensors can be smoother actua-
ted with different body parts and therefore can be smoother tampered
as well.
• For the use of sensors, the measuring cone should be adapted during
a review of the standards. The two-hand control panels of the type
SEPG05.3..., SEPK02.0... and SEP09.0... therefore are not BG-tested
in combination with the BWT sensors. If these sensors are used des-
pite that, either the minimum distance from the closest control element
with regard to the hazardous area must be calculated by means of the
equation
S = (K × T) + C
K = 1,600 mm/s, C = 250 mm
or a manual tampering by means of a combination of one hand and
other body parts or using simple tools must be prevented.
• Note: additional information can be found in our list ZHS/08 and DIN
EN 574.
Installation instructions: II
The relay must only be wired as shown in the wiring examples. Any
parallel- or series-wiring of the BWT relay contacts neutralises the safe
function of the devices. The downstream contactors or relays must be
equipped with positive-guided contacts and monitored in the feedback
circuit.
To trigger a hazardous movement, all sensors of the BWT must be
used. An output signal is generated, when both sensors are actuated
within a timeframe smaller than or equal to 0.5 s. The sensors must be
procured and arranged so their disabling by simple means or inadver-
tent actuation is prevented.
The distance between the sensors can be reduced, when one or more
partitioning walls are installed to prevent that the sensors are reached
with the extremities of a 260 mm long wire, representing the hand span.
The sensors must be arranged on a horizontal or nearly horizontal
surface with a distance of at least 1,100 mm to the loor or the access
area. This distance must be observed, when it is ensured by suitable
protective measures that no other body part (e.g. knee, hip) can trigger
an actuation in combination with one hand.
