lol
In what form is this information stored?
Bits
In what manner are data files organized?
Data files are organized by the type of data they contain.
Identify the sequence of events involved in a PLC scan cycle.
During a PLC scan cycle, the processor reads all the inputs, takes these values, and energizes or de-energizes the outputs according to the user program.
How are the contacts and coil of a rung identified?
Each contact or coil symbol is referenced with an address that identifies what is being evaluated and what is being controlled.
What is another common name for this instruction? Another name for the Examine If Open instruction is the BLANK instruction.
Examine-off
What is another common name for this instruction? Another name for the Examine If Closed instruction is the BLANK instruction.
Examine-on
Under what condition is the status bit associated with this instruction 0?
If a true logic path cannot be established or rung conditions go false, the OTE instruction is de-energized (0) and the output device wired to it is switched off.
Under what condition is the status bit associated with this instruction 1?
If a true logic path is established with the input instructions in the rung, the OTE instruction is energized (1) and the output device wired to its terminal is energized.
A normally open limit switch is to be programmed to control a solenoid. What determines whether an Examine-on or Examine-off contact instruction is used?
If the contacts need to close to energize the output, then the Examine If Closed is used.
Identify the appropriate comparison between the way horizontal and vertical scan patterns examine input and output instructions.
In the horizontal scan pattern, the processor examines input and output instructions from the first command, top left in the program, rung by rung. In the vertical scan pattern, the processor examines input and output instructions from the top left command entered in the ladder diagram, column by column and page by page.
When are input branch instructions used as part of a ladder logic program?
Input branch instructions are used in an application program to allow more than one combination of input conditions.
Identify the basic makeup of a ladder logic rung.
It consists of a set of input conditions, represented by contact instructions, and an output instruction at the end of the rung, represented by the coil symbol.
A limit switch with a single NO contact connected to the PLC discrete input module.
LS1 A |--] [---( )--| | LS1 B | |--]/[---( )--|
A limit switch with a single NC contact connected to the PLC discrete input module.
LS1 A |--]/[---( )--| | LS1 B | |--] [---( )- -|
Click and drag the following discrete input and output addresses to their SLC 500 format.
Limit switch connected to terminal screw 4 of the module in slot 1 of the chassis) I:1/4 Pressure switch connected to terminal screw 2 of the module in slot 3 of the chassis) I:3/2 Pushbutton connected to terminal screw 0 of the module in slot 6 of the chassis) I:6/0 Pilot light connected to terminal screw 13 of the module in slot 2 of the chassis) O:2/13 Motor starter coil connected to terminal screw 6 of the module in slot 4 of the chassis) O:4/6 Solenoid connected to terminal screw 8 of the module in slot 4 of the chassis) O:4/8
Click and drag the symbols and the equivalent instructions to their results.
NO contact) -Examine if closed (XIC) -Examine-on - -] [- NC contact) -Examine if open (XIO) -Examine-off - -]/[- Coil) -Output energize - -( )-
Does this mean it must be represented by a normally closed contact in the ladder logic program?
No
What part of an electromagnetic relay does this instruction look and act like?
OTE instruction looks and operates like a relay coil.
What does the memory map for a typical PLC processor consist of?
Program and data files
Click and drag the given descriptions to their PLC modes of operation.
Program) Used to enter a new program or update an existing one in the internal RAM memory Test) Used to operate or monitor the user program without energizing any outputs Run) Used to execute the user program with input devises being monitored and output devices energized accordingly
Identify the purpose of Windows based programming software such as RSLogix.
RSLogix is used to develop and monitor ladder logic programs.
Identify the reason for that.
The action of the field devices should be separated from the action of the PLC bits.
What does the address assigned to an instruction indicate?
The address assigned to an instruction indicates what PLC input is connected to what input device and what PLC output will drive what output device.
What information is stored in the input image table file?
The input image table file stores the status of the input terminals for the controller.
What information is stored in the output image table file?
The output image table file stores the status of the output terminals for the controller.
Identify the difference between the functions of the PLC program and data files.
The program files are the part of the processor memory that stores the user ladder logic program, whereas the data files store the information needed to carry out the user program.
What is this instruction asking the processor to do?
This instruction signals the PLC to energize (switch on) or de-energize (switch off) the output associated with it.
What is this instruction asking the processor to examine? This instruction asks the PLC's processor to examine if the contact is BLANK.
open
What state does this instruction assume when it is false? When the XIC instruction is false it will act like a(n) BLANK relay contact.
open
Under what condition is the status bit associated with this instruction 0? The status bit associated with the XIO is 0 when the address associated with the XIO is BLANK.
true
Under what condition is the status bit associated with this instruction 1? The status bit associated with the XIC is 1 when the address associated with the XIC is BLANK.
true
Under what condition is this instruction logically true? This instruction is logically true when the status of the input (physical) device or internal (logical) relay address associated with that bit is BLANK.
true
Under what condition is the status bit associated with this instruction 0? The status bit associated with the XIC is 0 when the address associated with the XIC is BLANK.
false
Under what condition is the status bit associated with this instruction 1? The status bit associated with the XIO is 1 when the address associated with the XIO is BLANK.
false
Under what condition is this instruction logically true? This instruction is logically true when the status of the input (physical) device or internal (logical) relay address associated with that bit is BLANK.
false
Identify the matrix limitations that may apply to certain PLCs.
-A maximum of seven parallel lines -Ten series contacts per rung
Identify the program used to solve the problem of a nested vertical programmed contact as shown in the given figure.
-A-----Y -C-B-| -C-D-|
Identify the program used to solve the problem of some logic ignored in the given figure.
-A-B-----Y -A-C-D-| -E-D----| -E-C-B-|
Identify the program used to solve the problem of a nested contact as shown in the given figure.
-A-B---Y -C-D-| -E-D-|
Identify the program used to solve the problem of too many series contacts (only four allowed) in the given figure.
-A-B-C-D---X -X-E---------Y
Electrical devices and signals can be divided into two categories: analog and digital. Identify the properties of these two categories.
-Analog signals can take any shape and represent an infinite number of possible values. -Digital devices operate using discrete ON or OFF signals that have only two possible values.
SLC 500 controller
-Status data file -Binary data file -Timer data file -Counter data file -Control data file -Integer data file -Floating-point data file
Identify the factors that enter into the length of the scan time.
-The speed of the processor module -The length of the ladder program -The actual ladder true/false conditions -The type of instructions executed
Match the following descriptions with their corresponding standard PLC languages as defined by the International Standard for Programmable Controllers. 1.Instruction List (IL) 2.Ladder Diagram (LD) 3.Function Block Diagram (FBD) 4.Structured Text (ST) 5.Sequential Function Chart (SFC)
2-A graphical depiction of a process with rungs of logic, similar to the relay ladder logic schemes that were replaced by PLCs. 3-A graphical depiction of process flow using simple and complex interconnecting blocks. 5-A graphical depiction of interconnecting steps, actions, and transitions. 1-A low-level, text-based language that uses mnemonic instructions. 4-A high-level, text-based language such as BASIC, C, or PASCAL specifically developed for industrial control applications.
When is the ladder rung considered as having logic continuity?
A ladder rung is considered to have logic continuity when at least one left-to-right true logical path exists.
Assuming the hardwired circuit drawn in the given figure is to be implemented using a PLC program, click and drag the devices to their descriptions.
All input field devices) -PB1, LS1, PS1, SS1, LS2, LS3, PB2, PB3, LS4 All output field devices) -PL1, SOL A, SOL B, SOL C, PL2 All devices that could be programmed using internal relay instructions) -CR1, CR2, CR3
Click and drag the instructions that are selected for each of the given discrete input field devices to accomplish the desired task.
Turn on a light when a conveyor motor is running in reverse. The input field device is set of contacts on the conveyor start relay that close when the motor is running forward and open when it is running in reverse.) -XIO (Examine if open) When a pushbutton is pressed, it operates a solenoid. The input field device is a normally open pushbutton.) -XIC (Examine if closed) Stop a motor from running when a pushbutton is pressed. The input field device is a normally closed pushbutton.) -XIC (Examine if closed) When a limit switch is closed, it triggers an instruction ON. The input field device is a limit switch that stores a 1 in a data table bit when closed.) -XIC (Examine if Closed)
In what way does an internal output differ from a discrete output?
Unlike a discrete output, an internal output does not directly control an output field device.
Under what condition does a ladder logic rung have logic continuity?
When there is a continuous path of true conditional instructions in a rung
Compare the way memory space is assigned and referenced in rack-based and tag-based PLCs.
With rack-based addressing a fixed device with a fixed address is used, whereas tag-based addressing is more flexible and uses text-based addressing.
What is this instruction asking the processor to examine? This instruction asks the PLC's processor to examine if the contact is BLANK.
closed
What state does this instruction assume when it is false? When the XIO instruction is false it will act like a(n) BLANK relay contact.
closed
