Specifications

3
Operation of enabling switches
Position 1
Position 2
Position 3
1. Press lightly
2. Release
3. Press tightly
4. Release
OFF
OFF
Terminal Contact Movable Contact
ON
The requirement for operation of 3-position enabling
switches (according to IEC 60204-1; 9.2.5.8):
When an enabling device is provided as a part of a
sys tem, it shall be designed to allow motion when
actuated in one position only. In any other position
motion shall be stopped.
– for a three-position type:
position 1: off-function of the switch •
(actuator is not operated)
position 2: enabling function •
(actuator is operated in its mid position)
position 3: off-function •
(actuator is operated past its mid position)
When returning from position 3 to position 2, the
function shall be ended.
Disparity Detection Circuit
for Dual Contacts
2-circuit
input
Agree
Enabling
Device
Both ON
Both OFF
Disagree
One ON, the
other OFF
Machine can
operate (normal)
Machine cannot
operate (normal)
Machine cannot
operate (failure of
enabling switch,
machine cannot
restart)
Enabling switch is attached
to the interlock switch—
machine operates auto-
matically.
Enabling switch is
detached from the inter-
lock switch—machine
can be operated only
manu ally.
A method of changing an operation mode (auto/
manual) using the HS5B interlock switch and
grip style enabling switch (HE1G)
Disparity detection of two contacts
A high level of safety—safety category 3 or higher (ISO 13849- •
1)—is required when an operator works near a hazard inside a
safety guard.
When released to position 1, the contacts are opened (turned
off) by the force of a released spring. The 3-position enabling
switches must be prepared for failures such as contact welding
and short-circuits, and a dual circuit is provided. Even if one
contact fails, the remaining contact can disable machine
operation. Furthermore, a disparity detection circuit is provided
so that machine operation is disabled when a disparity between
the two circuits is detected using a safety relay module.
International standards on enabling
switches
IEC 60204-1: 1997
9.2.4 Where it is necessary to suspend safeguarding, (e.g. for
set ting or maintenance purposes), a mode selection device or
means capable of being secured (e.g. locked) in the desired mode
shall be provided so as to prevent automatic operation. In addition,
one or more of the following means shall be provided:
- a portable control station (e.g. pendant) with an emergency stop
device and, where appropriate, an enabling device. Where a
porta ble station is in use, motion may be initiated only from that
station.
ISO 12100-2: 2003 Control mode for setting, teaching, pro-
cess changeover, fault-fi nding, cleaning or maintenance
4.11.9 Where, for setting, teaching, process changeover, fault-
fi nd ing, cleaning or maintenance of machinery, a guard has to
be dis placed or removed and/or a protective device has to be
disabled, and where it is necessary for the purpose of these
operations for the machinery or part of the machinery to be put in
operation, safety of the operator shall be achieved using a specifi c
control mode which simultaneously:
- permits operation of the hazardous elements only by continuous
actuation of an enabling device, a hold-to-run control device or a
two-hand control device.
ANSI/RIA R15.06
The pendant or teaching control device shall have an enabling
device using a three position switch which, when continuously held
in a detented position, permits motion. Release of or compression
past the midpoint detent of the device shall stop robot motion using
cir cuitry consistent with 4.5.
Note: Tests have shown that human reaction to an emergency may be to
release an object, or hold on tighter, thus compressing an enabling
device. Design and installation of the enabling device should
consider the ergonom ics issues of sustained activation.
ANSI B11.19, 12.3.1.3
Enabling devices shall be designed and constructed to permit
limited and supervised machine motion while personnel are inside
a hazard area.
A1 S33 S34 13 23 33
A2 S11
S1
Safety Output
F1
L (+)
24V DC
N (–)
ESC
HR1S-AF
Safety Relay Module
Enabling
Switch
S12 S21 S22 14 24 34
External
Start Condition