CE Conformity, Directives and Standards
KeTop T50VGA
146
User's Manual, Version: 1.3
© KEBA 2007
In contrast to the red/yellow emergency stop button there is no need to
switch the stop output signals of the radio receiver into the machine’s nor-
mal emergency stop circuit. It can also be used to stop individual safety
zones of a machine or plant, where functions such as “Safe operational
stop” can be triggered. This means that the drive components are safely
maintained in controlled shutdown by means of active, powered drives
(stop category 2 in accordance with EN 60204-1). This can prevent the loss
of reference data and facilitates fast restart of the machines.
The trained handheld terminal or machine operator is aware of the function
assigned to the button and knows the current operating mode in each case
as well as the current assignment of the machine. For this reason the col-
ouring is not disadvantageous to the machine operator.
The safety gain is that, in the case of inactive or unassigned equipment, no
danger of confusion is presented to third parties in respect of functional
emergency stop buttons.
14.2.9.3 Temporary plug-in handheld terminals: Stop button
Some cabled equipment is provided with a quick-release connector (e.g.
bayonet) that makes it possible to plug in and unplug the handheld terminal
quickly and ergonomically whilst the machine is in operation. Such hand-
held terminal’s are provided for frequent alternation of operation between
one or more machines and are needed there on a temporary basis, for
commissioning or setting up purposes.
By means of several measures, such as bridging connectors or relay cir-
cuits, the emergency stop circuits of the machine are bridged when the
handheld terminal is unplugged so that the machine can also continue to
run in normal operation without the handheld terminal. Start-up and opera-
tion of the machine can then take place using an independent operating
device.
These handheld terminals share the same problems as the radio terminals,
since due to frequent plugging and unplugging it cannot be ruled out that
disconnected handheld terminal’s with ineffective stop buttons may be left
lying or hanging temporarily in a machine shop or factory in the neighbour-
hood of working machines and may be mistaken for functional units in an
emergency situation.
This special case is not clearly treated in the corresponding Standards.
However, in the Product Standards for presses (EN 692:2004,
EN 693:2001, EN 12622:2001, and EN 13736:2003) one finds the following
clear statement:
“Any disconnectable control station shall not incorporate an emer-
gency stop button if the press can be operated while this controls sta-
tion is disconnected.”
Further Product Standards are currently under review.