Ch 1 plc
is a label or number that indicates where a certain piece of information is located in a PLC's memory.
Address
➢Each input and output device is given an _____, which lets the PLC know where it is connected.
Address
The PLC's memory system stores information about the status of all the inputs and outputs. To keep track of all this information, it uses a system called
Addressing
input and output devices have an infinite number of values.
Analog
The ___interface module accepts an analog signal and converts it to a digital signal.
Analog input
The ___module accepts a digital signal and converts it to an analog signal that operates the output.
Analog output
The ____ or ____module runs user written BASIC and C programs.
BASIC or ASCII
The ____enables a PLC to operate devices that require BCD-coded signals such as seven-segment displays
BCD-output module
Depending on memory type, 1 K can mean 1024 ___, 1024 ____, or 1024 ____
Bits/bytes/words
The___monitors the inputs, evaluates the ladder program, and turns on/off the appropriate outputs.
CPU
____,____&____are all terms used by different manufacturers to denote the same module that performs basically the same functions.
CPU, controller, and processor
4 major sections of PLC
CPU, output/input module, power supply, programming device
Typical analog inputs and outputs vary from
0 to 20 milliamps, 4 to 20 milliamps, or 0 to 10 volts.
➢When dealing with computer or PLC memory, however, ______, because this measurement is based on the binary number system (210 = 1024).
1 K means 1024
The I/O (Input/Output) system forms the interface by which ______ are connected to the controller.
Field devices
_______ refer to all devices that are physically wired to the PLC.
Field devices
Input/output arrangements are built into a ____PLC.
Fixed
comes in one package with no separate removable units.
Fixed I/O
➢View a process - or a ____ of a process on a monitor ➢ Determine how the system is running, trend values, and receive ______
Graphical location/ alarm conditions
software allows the user to monitor and control the process.
Human Machine Interface
A____can be connected to communicate with a PLC and to replace__________. Also to input ____ and ____
Human Machine Interface (HMI) pushbuttons, selector switches, pilot lights, thumbwheels, and other operator control panel devices. operational and maintenance commands
The _____of a PLC is the section to which all field devices are connected and provides the interface between the field devices and the CPU.
I/O section
The _________forms the interface by which field devices are connected to the controller.
I/O system
Unlike PCs, the PLC is designed to operate in the
Industrial environment
_____ such as pushbuttons, limit switches, and sensors are hardwired to the ________ terminals.
Input devices/ input module
accept signals from the machine or process devices and convert them into signals that can be used by the controller.
Input modules
The ____for a particular PLC lists the different types of instructions supported.
Instruction set
➢Memory size is usually expressed in _____: 1 K, 6 K, 12 K, and so on.
K values
_____is the most popular programming language
Ladder logic
The processor requires memory for storing the results of the _________ performed by the microprocessor as well as the _____ and the _____
Logical operations, operating system, PLC program
is the part of a PLC controller that stores data, instructions, and the control program.
Memory
____types use external I/O modules that plug into the PLC.
Modular
is divided by compartments into which separate modules can be plugged.
Modular I/O
An ______is used to provide electrical isolation between the power and logic circuitry.
Optical isolator
________ such as motor starters, solenoid valves, and indicator lights are hardwired to the _____ terminals.
Output devices/ output module
convert controller signals into external signals used to control the machine or process.
Output modules
A ___ is an industrial grade computer that is capable of being programmed to perform control functions.
PLC
in this mode the processor is prevented from executing the ladder program. Also allows the technician to perform program edits.
PROGRAM
A _____ is the most commonly used programming device.
Personal computer
The most popular method of PLC programming is to use a ____ in conjunction with the manufacturer's programming software.
Personal computer
The PLC ___provides the necessary power to the processor and I/O modules plugged into the backplane of the rack.
Power suplly
provides DC power to all modules that plug into the rack. For large PLC systems, this power supply does not normally supply power to the field devices.
Power supply
consists of a microprocessor for implementing the logic and controlling the communications among the modules.
Processor
A _____ is a series of instructions that directs the PLC to execute actions.
Program
A ______is used to create and enter the desired program into the memory of the processor.
Programming device
A___is needed to enter, modify, and troubleshoot the PLC program.
Programming terminal device
PLCs use ____as a ____ area of data that may need to be quickly changed. RAM is volatile so battery backup is required for it to avoid losing data in the event of a power loss
RAM/ temporary storage
places the processor in remote mode.
REM
For the program to operate, the controller is placed in the ____ mode.
RUN
in this mode the processor executes the ladder program and energizes output devices.
RUN
Nonvolatile ____stores programs, and data that cannot be changed after the memory chip has been manufactured.
Read Only Memory (ROM)
PLCs operate in _____, which means that an event taking place in the field will result in the execution of an operation or output.
Real time
_______, the standard programming language, is based on electromagnetic relay control.
Relay ladder logic
Initially used to replace _____ its ever-increasing range of functions includes timing, counting, calculating, comparing, and the processing of analog signals.
Relay logic
The PLC program is executed as part of a repetitive process referred to as a _____
Scan
The _____is the time required for one complete execution of the user program.
Scan time
are used to establish point-to-point connections with other intelligent devices for the exchange of data.
Serial communications modules
PLCs execute a _____program in an orderly and sequential fashion from first to last instruction.
Single
is the physical location of the I/O module in a chassis.
Slot number
Increased Reliability - Since all the logic is contained in the PLC's memory, there is no chance of making a logic wiring error. PLCs also offer the reliability associated with ______
Solid state components
When not in use, store modules in a
Static shield bag
determines if an input or output is being addressed.
Type
are used to identify the terminal connection in a particular I/O module.
Word and bit
The PLC comes with its program language built into its memory and has no permanently attached
keyboard, CD drive, or monitor.
The hardware assembly that houses I/O modules, processor modules, and power supplies is referred to as the
Chassis
To find and fix problems, users can display the ____ on a monitor and watch it in real time as it executes.
Control program
It is easier to _____ and _____ a program in a PLC than to wire and rewire a circuit.
Create / change
If the module is a ______, then the input or output device must be a _____
Current sinking module/ current sourcing device
If the module is a _____module, then the input or output device must be a _____.
Current-sourcing/ current sinking device
The ___interface module connects field input devices of the ON/OFF nature.
Discrete I/O
Many electronic components found in processors and other types of PLC modules are sensitive to ___voltages that can degrade their performance or damage them.
Electrostatic
Certain DC I/O modules specify whether the module is designed for interfacing with ___ or ____devices
current-source or current-sink devices.
