Banner SC22-3E Safety Controller with Ethernet - Manual (Page 107)

The Safety Controller Emergency Stop configuration prevents muting or bypassing of the E-Stop input(s). However,
the user still must ensure that the E-Stop device remains active at all times.
WARNING: . . . Reset Routine Required
U.S. and international standards require that a reset routine be performed after clearing the cause of a stop condition (e.g.,
arming an E-stop button, closing an interlocked guard, etc.). Allowing the machine to restart without actuating the nor-
mal start command/device can create an unsafe condition which could result in serious injury or death.
10.7.2 Emergency Stop Push Button Requirements
As shown in the following figures, the E-stop switch must provide one or two contacts for safety which are closed when the switch is
armed. Once activated, the E-stop switch must open all its safety-rated contacts, and must require a deliberate action (such as twisting,
pulling, or unlocking) to return to the closed-contact, armed position. The switch must be a “positive-opening” (or direct-opening) type, as
described by IEC 60947-5-1. A mechanical force applied to such a button (or switch) is transmitted directly to the contacts, forcing them
open. This ensures that the switch contacts will open whenever the switch is activated.
Standards ANSI NFPA 79, ANSI B11.19, IEC/EN 60204-1, and ISO 13850 specify additional emergency stop switch device require-
ments, including the following:
• Emergency stop push buttons shall be located at each operator control station and at other operating stations where emergency
shutdown is required.
• Stop and Emergency stop push buttons shall be continuously operable and readily accessible from all control and operating stations
where located. Do not mute or bypass any E-stop button.
• Actuators of emergency stop devices shall be colored red. The background immediately around the device actuator shall be colored
yellow. The actuator of a push-button-operated device shall be of the palm or mushroom-head type.
• The Emergency stop actuator shall be a self-latching type.
NOTE: Some applications may have additional requirements; comply with all relevant regulations.
Safety Circuit Integrity Levels and Multiple E-Stop Buttons
As part of the required risk assessment for the machine, ANSI NFPA 79 and IEC/EN 60204-1 state that the safety performance (integrity)
must reduce the risk from identified hazards as determined by the risk assessment. See section
10.1 Safety Circuit Integrity and ISO
13849-1 (EN954-1) Safety Circuit Principles on page 90 for guidance if the requirements as described by ISO 13849-1 (EN954-1) are to
be implemented.
In addition to the requirements stated above, the design and the installation of the emergency stop device (e.g., switch, button, or rope-
pull) must be such that the possibility of a catastrophic failure of the device resulting in the loss of the safety function must be excluded
(designed out). The device must comply with ISO 13850 requirements such that the fault exclusions of ISO 13849-2 are applicable.
Electromechanical devices that have contacts designed in accordance to IEC 60947-5-1 Annex K and that are installed per manufactur-
er’s instructions are expected to open when the emergency stop device is actuated.
WARNING: . . . Multiple Switching Devices
Whenever two or more devices are connected to the same safety module (controller):
• Contacts of the corresponding pole of each switch must be connected together in series. Never connect the con-
tacts of multiple switches in parallel. Such a parallel connection defeats the switch contact monitoring ability of the
Module and creates an unsafe condition which could result in serious injury or death.
• Each device must be individually actuated (engaged), then released (or re-armed) and the safety module reset.
This allows the module to check each switch and its wiring to detect faults.
This check must be performed during the prescribed checkouts. Failure to test each device individually in this manner
could result in undetected faults and create an unsafe condition which could result in serious injury or death.
SC22-3/-3E Safety Controller Instruction Manual
P/N 133487 rev. C www.bannerengineering.com - tel: 763-544-3164 107