Introduction to PLC lessons 1-4

Tinted , arc-rated ? should be warn when working on any PLC system that has voltages over 50 volts or in any environment where arc flashes are possible

face shields

number of I/O in a NANO PLC

less than 16 I/O

PLC's provide rigid control for cycle automation, minimizing ?

manual intervention

Number of I/Os in a Large PLC

more than 512

What industry would use a PLC to monitor a corrugation machine

pulp and paper

common terms used to describe DC positive polarity

source or supply

Why must technicians wear insulating electric gloves and use insulated tools to test instruments?

to prevent resistance

A ? is used to manage wire connections between PLC Inputs/outputs and electrical devices/components

Terminal block

A ? switch circuit typically uses a sink or source transistor as the switching device

Three wire input NPN (sink) PNP (source)

What is a Modular form factor PLC

Variable number of input/output terminals base on cards or modules

Briefly describe steps of inspecting PLC

1) ensure the PLC and all associated hardware is securely mounted in a proper location 2) check all wire connections 3) grounding

List three examples of input devices

1) push button 2) prox switch 3) Selector switch 4) limit switch

PLCs using a fixed voltage for the power supply are typically rated at ? Volts

115 VAC +5% to -10%

number of I/Os in a medium PLC

129- 512

Number of I/Os in a Micro PLC

16-128

What are the common resistance values for grounding electronic equipment that manufactures often specify

5 ohms 3 ohms 1 ohm or less

how many bits are in a byte

8

what type of Gate logic is represented by any number of normally opens switches connected in series

AND Logic

Output such has lights, motors, and valves are typically connected as what type of circuit

Parallel

Why must extra care be taken when using a force command

Because it overrides all safety features

A PLC ? overheat and become a fire hazard

Can

common terms used to describe DC negative polarity

Common or sink

Example of the function of a PLC in an elevator system

Direct the lift accordingly

what is the formula to determine total resistance in a series circuit

E/I= R

Will the total resistance in a parallel circuit always going to be higher or lower than the lowest resistance value of any given load

Lower

Normally closed (NC) switch that is ? operated will have the operator of the switch drawn above the terminals of the switch

Mechanically or automatically

What size of PLC's typically contain rack mounted I/O modules

Medium/large

The output sections of ? PLC's have 6 relay contacts

Micro

the input section of a ? PLC contains 4-6 digital and 2-4 analog input terminals, while the output section has 4 relay contacts

Nano

What type of electric equipment are PLC's considered to be that requires them to be mounted in and enclosure

Open Type

what is the function of a PID instruction

Output instruction used to control set point of a variable inside control logic. ( temp, flow, pressure, level)

Wha is the function of the housekeeping and overhead section of the operating cycle

PLC performs memory management and updates timers and counters

What is the most common programming device used to program PLCs

Personal computers

Symbol for an activated (NO) manual switch

Pg 120

A ? is helpful in showing what additional components can be added to a system and what function a device or component has within the system

Pictorial Drawings

What type of devices are bit instructions programmed for

Relay type device

The voltage drop across any two loads are the same if the ? values of the loads are the same

Resistance

How are bits numbered

Right to left starting at 0

what is a program scan

Section of operating cycle in which PLC examines PLC program compares program status inputs determine output

In a ? circuit, current stops flowing any time a fuse blows, a circuit breaker trips or a switch opens

Series

what is a Fixed Form Factor PLC

Set number and type of input and out put terminals

Regarding PLC installation guidelines what do all PLC installations start with

Sufficient number of emergency stops and a master control relay

The standard unit of of memory for a PLC is the ?

Word

Describe the point to point wiring method

where each component in a circuit is connected (wired) directly to the next component as specified by wiring or line diagrams