Disconnecting main power -4 safety circuits -4 – Rockwell Automation 1764-xxxx MICROLOGIX 1500 PROGRAMMABLE CONTROLLERS User Manual

Page 30

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Publication 1764-UM001B-EN-P - April 2002

2-4 Installing Your Controller

Use only the following communication cables in Class I, Division 2
hazardous locations.

Disconnecting Main Power

The main power disconnect switch should be located where operators
and maintenance personnel have quick and easy access to it. In
addition to disconnecting electrical power, all other sources of power
(pneumatic and hydraulic) should be de-energized before working on
a machine or process controlled by a controller.

Safety Circuits

Circuits installed on the machine for safety reasons, like overtravel
limit switches, stop push buttons, and interlocks, should always be
hard-wired directly to the master control relay. These devices must be
wired in series so that when any one device opens, the master control
relay is de-energized, thereby removing power to the machine. Never
alter these circuits to defeat their function. Serious injury or machine
damage could result.

Table 2.1 Cables for Use in Class I, Division 2 Hazardous Environment

1761-CBL-PM02 Series C or later

2707-NC8 Series B or later

1761-CBL-HM02 Series C or later

2707-NC9 Series B or later

1761-CBL-AM00 Series C or later

2707-NC10 Series B or later

1761-CBL-AP00 Series C or later

2707-NC11 Series B or later

WARNING

!

EXPLOSION HAZARD

Do not replace components or disconnect
equipment unless power has been switched off.

WARNING

!

EXPLOSION HAZARD

Do not connect or disconnect connectors while
circuit is live.

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