Enabling Switch; Overview - Omron NSH5 - 10-2010 Operation Manual

Enabling Switch

3-3 Enabling Switch
3-3-1

Overview

External Connection
Diagram
38
In contrast to the emergency stop switch, which lets a worker intentionally
stop the machine in case of an emergency, the enabling switch makes it eas-
ier to avoid danger with no conscious decision by a worker. When work is
required in hazardous areas, e.g, during maintenance, devices with enabling
switches provide an important safety measure by preventing unexpected
operations from occurring while work is underway in the those areas.
Manual operation of devices is permitted while the enabling switch is lightly
pressed. At soon as a hazardous situation arises, however, operation is
stopped if the worker instinctively either lets go of the enabling switch or
grasps it more tightly.
Some standards, such as the ANSI/RIA R15.06 and CSA/Z434-03 Industrial
Robot Standards and the ANSI/B11.19 Machine Tool Standards, require the
use of enabling switches. In EN 60204-1, enabling switches are not required
but are recommended as auxiliary devices.
Enabling switch
ON
OFF
The status of the enabling switch's DPST-NO contact is output externally
using a hard-wired output from the Special Cable.
NSH5
Enabling switch
DPST-NO
ENB1 ENB2
Hard-wired DPST-NO contact (3-position)
Ordinary pressure: Pressed in:
Turns OFF
Turns ON
Special Cable
ENB1A1
ENB2A1
ENB2A2
ENB1A2
Section 3-3
Pressure
Safety
circuit