When Replacing Modules or Working on Equipment Controlled by the PLC

question 88

Multiple Choice

When replacing modules or working on equipment controlled by the PLC installation,the safest way to proceed is to:

• A)de-energize the MCR coil.
• B)block open the emergency stop switch.
• C)remove the fuse from the circuit.
• D)pull and lock the disconnect switch.

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Definitions:

Difference Threshold

The minimal change in stimulus that can just barely be detected by an organism, also known as the just noticeable difference (JND).

Trichromatic Theory

A theory of color vision proposing that colors are perceived through the relative rates of response by three kinds of cones, each one sensitive to a range of wavelengths.

Opponent-process Theory

A psychological and physiological model that explains how humans perceive colors as the result of complex interactions between various neurons that process color in an antagonistic manner.

Somesthetic Senses

A group of senses that includes the sensations of touch, temperature, body position, and pain, originating from muscles, joints, skin, and other internal receptors.