Programmable logic controllers 2

Which language is used for large process controls where several complex functions take place?

Sequential function chart

The most common type of analog cable is ?

Shielded twisted pair

The two most common standards of analog signals are?

0v to 10v 4mA to 20mA

Smaller PLC's may have fewer then ____ I/O points

10

Large PLC systems may have more then _____ I/O points

120,000

_________ devices that operate over a range of values of voltage or current?

Analog

The _________ is the power and communication bus for the PLC components?

Backplane

The major hardware components of a modular PLC system are?

Power supply Backplane Processor (cpu) Input/output (I/O) modules

The processor carries out its functions in a sequence called the?

Processor scan

List the 3 types of memory used in a PLC?

RAM- random access memory ROM- read only memory EEPROM- electrically erasable programmable memory

Which types of memory are volatile and which are non volatile?

RAM- volatile ROM- non-volatile EEPROM- considered non volatile but can be programmed

What are the primary functions of a PLC processor?

Read an store the status of all the input devices Execute the user program by solving the programs logic Update the status of all the outputs

A PLC that is a complete unit is often called?

Shoebox PLC

Can a remote module have several input or output devices connected to it and only have one cable back to the PLC? T/F

True

Is a thermal overload contact an example of a discrete device? T/F

True

The circuits for the input/ output devices may connect to the input/ output modules, but are they isolated from the backplane, PLC power supply and CPU? T/F

True

What would you use to reduce the amount of cabling between the PLC and I/O devices?

Use a remote I/O

___________ devices that are either on or off?

Discrete

One way to expand a PLC system is to add another PLC and link the two or a group together with a___________ ____________ ____________?

Communication data highway

List 4 advantages of a plc over relay control?

Expandability Programmability Reliability Cost

Which module receives signals from sensing devices?

Input

Receives signals from sensing devices?

Input module

What are the 3 basic components of a control system?

Inputs Outputs Controller

For outputs that require larger currents then an electronic switch can handle what would you use?

Interposing relay. ( a relay coil operated by a solid state switch)

Which PLC language is the most common

Ladder diagram

Which programming language resembles a schematic diagram?

Ladder diagram

List 3 languages used for programming PLC's

Ladder diagram (LD) Function block (FBD) Sequential functions ( flow ) chart (SFC)

A data highway is ________ ________ _____ cabling that connects a number of PLC's or PLC's and personal computers for the exchange of data.

Local area cabling (LAN)

High speed counters, proportional integral derivative control (PID), and fuzzy logic control are what type of module?

Special I/O modules

A PLC has __________ _____________ switching that replaces the moving contacts of electromechanical relays.

Static electronic

List the 2 text based languages for programming a PLC

Structured text (ST) Instruction lists (IL)