Rockwell Automation Allen-Bradley MobileView Guard G750 Démarrage Rapide page 11

Emergency Stop Switch
The emergency stop switch of the MobileView terminal meets the requirements of
EN 418. It must be designed as an emergency stop of category 0 or category 1 (see
EN 60204-1, chapter 9.2.5.4.2) on the basis of the risk assessment for the machine.
The connection of the positive-break contacts to an appropriate monitoring system
must meet the safety category which is defined by means of the risk assessment (in
accordance with EN954-1) of the machine.
The emergency stop has 2, potential-free, normally closed contacts for connecting
external peripherals, a nominal operating voltage of 24V (Safety Extra Low Voltage
in accordance with EN 61131-2 and EN 50178), and a maximum operating current
of 500 mA.
ATTENTION
!
Risk Assessment of Machinery
For the risk assessment, the following standards must be applied:
• EN 292-1 "General principles for design of machinery"
• EN 1050 "Principles for risk assessment of machinery"
• EN 954-1 "Safety-related parts of control systems"
• ANSI/RIA 15.06-1999 "American National Standard for Industrial Robots and
Robot Systems - Safety Requirements (Section 9)"
• ANSI B11.TR3-2000 "Risk Assessment and Risk Reduction - A guide to estimate,
evaluate and reduce risks associated with machine tools"
The safety categories (B, 1, 2, 3, 4) define the structure of safety-related parts of a
machine and are derived from this risk assessment.
Page 9 shows how the enabling function of the MobileView terminal meets safety category 3
using a PILZ PST 1 safety control relay. Please keep in mind, that the entire concept of the
machine must be layed out accordingly.
• When the emergency stop switch is not wired into the
emergency stop circuit, the MobileView terminal must be
stored where it is not available to operators.
Consider that the operator might instinctively activate the
nearest emergency stop in case of danger. This could have
fatal consequences if the emergency stop does not
function.
• Emergency stop functions must remain operational in all
operating modes. Resetting an activated emergency stop
must not result in uncontrolled startup of machines or
installations.
• The emergency stop switch does not replace other safety
devices.
MobileView Guard G750
Publication 2727-QS002E-MU-P
11