PLC

  1. The input and output interface used in PLC’s can take two forms.  What are they?
    • Fixed: A small or micro PLC system
    • Modular: racks and modules.  (Most common)
    •  Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 pp12
  2. The power and data interface for the modules is provided by? PLC's card set
    • The backpane that has copper conductors, called lands, that deliver power to the modules and also provide a data bus to exchange data.
    •  Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 PP 11
  3. What voltage level is used in the PLC central processor? PLC's card set
    Think low
    0-5 volts in the CPU.  Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 pp13
  4. DC modules can either be current _______ or current __________.  Depending on what? PLC's card set
    • Current sourcing (current flows out of the module when active) or current sinking (current flows into the module when active)
    •  Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 pp14
  5. The PLC ladder logic inputs are called what instead of contacts and why?
    The PLC ladder logic inputs are called instructions and not contacts because the input instructions only represent the value of a binary bit in the PLC memory.   Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 pp23
  6. Each rung of the PLC ladder logic represents a logical statement executed in software with inputs and outputs located where?
    Each rung of the PLC ladder logic represents a logical statement executed in software with inputs on the left and outputs on the right. Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 pp 22
  7. There are how many standard programming languages that are available for programming new applications?
    • Five:
    • Function Block Diagrams (FBD)
    • Instruction List (IL)
    • Structured Text (ST)
    • Sequential Function Charts (SFC)
    • Ladder Diagrams (LD)
    • Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 pp 4
  8. In ladder logic binary the addition is straight forward with one exception.  1+1=? why?
    • 1+1=0 with a carry of the one to the next most significant place value because only two digits are available.  1 & 0.
    • Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 pp 211
  9. the polarity of the ladder rungs in a plc ladder logic diagram is what from left to right?
    positive voltage (potential) on the left and neutral on the right.
  10. Binary code is what?
    A code in which a string of four binary digits represents a decimal number.
  11. The Boolean expression produces wither the Boolean value of 1 or 0 and these represent what statement?
    1 true and 0 false.  1 being positive voltage and 0 being no voltage. Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 pp479
  12. Typically, you use Boolean expression to condition what?
    You use boolean expression to condition the execution of other logic. Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 pp 479
  13. The Boolean logic for the Not Gate is drawn as what?  It represents 0 and 1 or 1 and 0 in the truth table.
    Image Upload 1
  14. The ladder logic for the not gate looks like what?  Not the boolean logic.
    Image Upload 2
  15. The AND gate is associated with the following symbol that can have any number of inputs but only one output.  Draw the Boolean logic gate symbol.
    Image Upload 3 one easy way to remember this is that it looks like the letter D which is the last letter in the word ‘and’.
  16. The statement “Not true” and “True” represent what electrical state.  How do you remember this?
    The statement “not true” is closed and “true” is open.  the number of letters in true and open versus closed and not open are fewer or more depending on the statement and this is how you can remember which one associates with which.
  17. The ‘and’ gate represents what mathematical function?
    Multiplication is the And gate.
  18. the ladder logic for an ‘and’ gate is drawn as what?
    Image Upload 4
  19. The OR gate is associated with the following symbol that also can have any number of inputs but only one output.  In Boolean.
    Image Upload 5
  20. This statement represents what Boolean logic statement? "The truth table below shows that the output is turned on (1) when any of the inputs are true (1).  An easy way to remember this is OR works like addition.”
    • The or gate.
    • Image Upload 6
  21. The ladder logic drawing for an “OR” Boolean statement is what?
    Image Upload 7 ‘or’ is addition and is also used in a parallel circuit versus ‘and’ which is used in a series circuit or multiplication.
  22. Examine if closed (XIC) is shown how (electrically) in the PLC ladder logic?
    In the open state.
  23. Examine if open (xio) is shown how (electrically) in the PLC ladder logic?
    In the closed state.
  24. Although “Not true” represents closed electrically it is important to remember that it is also representing what boolean decimal and what potential?
    Not true represents 0 in boolean logic and zero electrical potential at that point.
  25. Although “true” represents open electrically it is important to remember that it is also representing what boolean decimal and what potential? PLC's card set
    True represents 1 in boolean decimal form and potential at that point electrically.
  26. True in Logix 500 Allen Bradely PLC ladder rung programming shows in what color?
    True shows in the color Green in Logix 500 Allen Bradely ladder logic programming.  Versus not true which is dark grey
  27. In a PLC: The largest output module ampacity is how many amps in a PLC?
    .4 amps
  28. In a PLC: Because the controls can be either 0 to 10 volts or even 240 volts, you must always place what between the modules and the controls?
    A relay must be placed between the modules and controls to isolate the low and high voltage from each other.
  29. What mode will a PLC program always be ran in before running a program?
    A PLC program will always be ran in test mode before running a program.  If the upper left corner in Allen Bradely Logic 500, for instance, shows green then all statements are true.
  30. In a PLC What is replaced in the CPU module once every year and usually during a shut down?
    The battery is always replaced during a shutdown in the CPU once a year.
  31. A PLC rack will have how many modules?
    A rack can have 0-9 modules or a total of 10. Although you can have as many as 30
  32. How many PLC racks can there be to hold a total of 10 modules per rack?
    As many as 4.
  33. In PLC's the word IS would be associated with all devices that are?
    Normally open. “this normally open pushbutton passes current if it is pushed”.
  34. In PLC's The word not is associated with what state?
    Normally closed: “This normally closed pushbutton passes current if it is not pushed".
Author
johnbowens
ID
316881
Card Set
PLC
Description
using the sources: Programmable Logic Controllers; James A Rehg & Glenn J. Sartori, 2007 and Micheal D. Gorin JATC Local 332 class
Updated