Plan for e stops and machine interlocks, 2ć11 – Rockwell Automation 1771-QDC, D17716.5.87(Passport) CLAMP AND EJECT MODE User Manual

Page 32

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Install the QDC Module

Chapter 2

2-11

You must consider the installation of Emergency Stop switches and
machine interlocks when performing the following system tasks:

designing your system

assembling mechanical/hydraulic components

wiring system components

developing system ladder logic

ATTENTION: The Electrical Standard for Industrial
Machinery (NFPA 79-1987) requires an emergency stop that,
when actuated, shall de-energize all electrical power circuits
which provide electrical energy to sustain machine motion.
Maintained contact “Emergency Stop” push buttons are
recommended.

ATTENTION: The American National Standard for Plastics
Machinery -- Horizontal Injection Molding Machines -- for
Construction, Care, and Use (ANSI B151.1-1984) requires
hydraulic, mechanical, and electrical interlocks to prevent
inadvertent clamp closing with a safety gate in an open position.

In addition, we strongly recommend that the electrical
interlocks consist of redundant devices and that the control
circuit be so arranged that malfunction or improper sequencing
of either redundant device prevents further operation of the
machine.

ATTENTION: NEMA Standards Publication ICS1.1, Safety
guidelines for the Application, Installation, and Maintenance of
Solid State Control recommends that the emergency stop and
safety gate electrical interlocks should directly control their
appropriate functions through an electromechanical device
independent of the solid state logic.

The next page shows an illustration of a typical grounded PLC power
distribution circuit. For ungrounded systems or for more information on
grounding and wiring guidelines, refer to Allen-Bradley Programmable
Controller Wiring and Grounding Guidelines (pub. no. 1770-4.1) .

Plan for EĆSTOPs and

Machine Interlocks

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