Rockwell Automation Allen-Bradley MobileView 2711T-VMBRACKET, User Manual

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Rockwell Automation Publication 2711T-UM001E-EN-P - March 2019 19
Safety Precautions and Elements Chapter 2
Foreseeable Misuse of the Enabling Switch
Foreseeable misuse is when the enabling switch is modified so it stays in the
enabling position. The foreseeable misuse of the enabling switch must be
restricted. The following measures are recommended, which cause the machine
to stop in manual mode.
• Inquiry of the enabling switch when you turn on the machine/plant, and
inquiry of the enabling switch when you change the operating mode from
automatic to manual (the enabling switch must not be in the enabling
position).
• The enabling switch must be released within a defined time period and
pushed into the enabling position again, with the time length defined by
the activity.
Emergency Stop (E-stop)
Push Button The E-stop push button of a MobileView 2711T terminal meets the
requirements of ISO 13850. The button must be designed as a Category 0 or
Category 1 emergency stop by the risk assessment for the machine. The
connection of the force-guided contacts to an appropriate monitoring system
must meet the safety level that results from the risk assessment of the machine.
See
Risk Assessment of Machinery on page 20 .
The E-stop has two potential-free, normally closed contacts to connect external
peripherals, a nominal operating voltage of 24V (safety low voltage in accordance
with EN 61131-2), and a maximum operating current of 500 mA at 24V DC.
WARNING: E-stop push buttons (red-yellow in color) that are not fully
functional can have fatal consequences. E-stop push buttons must be effective
under all circumstances in all operating modes of a machine or plant.
• When the E-stop push button is not wired into an emergency stop circuit, the
MobileView 2711T terminal must be stored where it is not visible to operators.
• The reset of an activated E-stop push button must not result in the uncontrolled
startup of machines or installations.
• The E-stop push button does not replace other safety devices or E-stop buttons
mounted directly on machines.
• Do not use MobileView 2711T terminals with red-yellow E-stop buttons in
applications where the terminal is plugged in and out of junction boxes frequently
or meant for temporary use. Only MobileView 2711T terminals with gray stop push
buttons are meant for these applications.
• Test the functionality of the E-stop push button at least once every six months.
Verify that machine or plant operation stops when the button is pushed.
• When a MobileView 2711T terminal has been exposed to shock (for example, it is
dropped on the ground), test to verify that the E-stop push button still functions
properly.