Banner SC22-3E Safety Controller with Ethernet - Manual (Page 112)

10.9 Enabling Device
An enabling device is a manually operated control that, when continuously actuated, will allow a machine cycle to be initiated in
conjunction with a start control. Standards that cover the design and application of enabling devices include:
ISO 12100-1/-2
IEC 60204-1
ANSI/NFPA 79
ANSI/RIA R15.06
ANSI B11.19
See section 4.6.3 Enabling Devices on page 36 for more information.
10.9.1 Enabling Device Guidelines
Depending on the application, the use of the enabling device may require supervision and allow only limited machine operation when the
individual actuating the device is exposed to a hazardous situation. When the enabling device is in use, the control of machine motion
must be prevented from other sources that would override the function of the enabling device. Simply actuating the enabling device
should not create a hazard.
An enabling device allows a hazardous situation when continuously actuated in one position only. In any other position, the hazard must
be eliminated and the start function be inhibited.
Since an individual’s reaction to an emergency situation may be either to release or to tighten the grip, many standards require the use of
three-position devices:
• Position #1: the OFF function of the switch (actuator is not operated).
• Position #2: the enabling function (actuator is operated in its midpoint).
• Position #3: the OFF function of the switch (actuator is operated past its midpoint).
Release of, or compression past, the midpoint-enabled position (#2) of the device must initiate an immediate stopping of hazardous mo-
tion or situations. It is required that the enabling device be released and re-actuated before machine motion can be reinitiated.
If allowed, for two-position types, the positions are as follows:
• Position #1: the OFF function of the switch (actuator is not operated).
• Position #2: the enabling function (actuator is operated).
The stop function must be either a functional stop Category 0 or a Category 1 (see ANSI NFPA79 Section 9). The design and installation
of the enabling device must consider the ergonomic issues (force, posture, etc.) of sustained activation. A visual means of indicating that
the device is active may be required.
Only trained and qualified individuals are allowed to operate the enabling device if it is bypassing other safeguards. Safe work procedures
must include, but are not limited to, the use of the device, the associated hazards, and the task requiring the use of the device.
If more than one individual is to be safeguarded by the use of enabling devices, each individual must have their own device. Each ena-
bling device must be concurrently operated before machine motion can be initiated.
The means to return the machine to production mode must be located outside the hazardous area, where it can not be reached from
within that area and is guarded against unintended operation. In addition, the reset switch operator must have full view of the entire
guarded area and verify that the area is clear of individuals during the reset procedure.
10.9.2 Enabling Device Hookup Options
The device is shown in the actuated position (Stop) state.
SC22-3/-3E Safety Controller Instruction Manual
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