PLCs Flashcards
PICTORIAL DRAWING
A DRAWING RESEMBLING A PHOTOGRAPH OR 3-D PICTURE.
AND
NORMALLY OPEN, IN SERIES
OR
NORMALLY OPEN, IN PARALLEL.
NOT
NORMALLY CLOSED CONNECTED TO CONTROL A LOAD.
NOR
NORMALLY CLOSED, IN SERIES.
NAND
NORMALLY CLOSED, CONNECTED IN PARALLEL.
5 COMMON SECTIONS OF PLCS…
INPUT, OUTPUT, POWER SUPPLY, CPU, PROGRAMMING DEVICE
INPUT SECTION
TERMINAL SCREWS RECEIVE SIGNALS FROM INPUT DEVICES, SEND SIGNALS TO CPU.
OUTPUT SECTION
SIGNALS FROM THE CPU TO COMPONENTS.
POWER SUPPLY
CONVERTS VOLTAGE OF POWER SOURCE TO VOLTAGE REQUIRED BY CPU.
HOLD UP TIME
LENGTH OF TIME A PLC TOLERATES POWER LOSS WITHOUT AFFECTING OPERATION.
CPU
CENTRAL PROCESSING UNIT, HOUSES THE “BRAIN” OF THE PLC.
PROGRAMMING DEVICE
DEVICE WITH A KEYPAD, WRITE AND ENTER CONTROL PROGRAM INTO THE PLC.
FORM FACTOR
PHYSICAL CONFIGURATION, CONNECT THE COMPONENTS OF A PLC INTO A HOUSING.
FIXED PLC
PLC, SET NUMBER AND TYPE OF INPUT/OUTPUT TERMINALS.
MODULAR PLC
VARIABLE NUMBER OF INPUT/ OUTPUT TERMINALS BASED ON NUMBER OF CARDS.
LADDER DIAGRAM
DRAWING CONTAINS LOGIC FOR AN APPLICATION, USED TO TEST AND TROUBLESHOOT HARDWIRED APPLICATIONS.
PROGRAMMING RULE 1
EACH LINE OF A DIAGRAM IS REFERRED TO AS A RUNG.
PROGRAMMING RULE 2
ONE COMPONENT PLACED ON A RUNG. OUTPUT COMPONENTS CAN BE PLACED IN PARALLEL, NOT SERIES.
PROGRAMING RULE 3
INPUT DEVICES PROGRAMMED IN SERIES, PARALLEL OR SERIES/PARALLEL COMBINATIONS.
PROGRAMMING RULE 4
INPUT DEVICES AND OUTPUT COMPONENTS CAN BE PROGRAMMED IN NESTED BRANCHES.
PROGRAMING RULE 5
NESTED BRANCHES CANNOT OVERLAP.
PROGRAMING RULE 6
INPUT DEVICES CAN BE PROGRAMMED AT MULTIPLE LOCATIONS.
PROGRAMMING RULE 7
OUTPUT COMPONENTS CAN HAVE VARIOUS TYPES OF INSTRUCTIONS WITH THE SAME ADDRESS.
PROGRAMMING RULE 8
OUTPUT COMPONENTS ARE NOT PROGRAMED AT MULTIPLE LOCATIONS.
XIC (EXAMINE IF CLOSED)
TRUE 1 FALSE 0
XIO (EXAMINE IF OPEN)
TRUE 0, FALSE 1
OTE (OUTPUT ENERGIZE)
TRUE 1, FALSE 0.
TIMER INSTRUCTION
PROVIDE TIMING FUNCTIONS SIMILAR TO MECHANICAL OR SOLID-STATE TIMERS.
COUNTER INSTRUCTION
PROVIDE COUNTING FUNCTIONS SIMILAR TO SOLID-STATE COUNTERS.
TIME BASE
INSTRUCTION LABEL USED TO INDICATE THE UNIT OF TIME.
TIMER PRESET
NUMBER OF TIME BASE INTERVALS A TIMER INSTRUCTION IS PROGRAMMED TO ACCOMPLISH.
TIMER ACCUMULATED VALUE
LENGTH OF TIME THAT A TIMER HAS BEEN TIMING.
TIMER OFF-DELAY
USED TO DELAY THE SHUT DOWN OF MACHINERY.
RETENTIVE TIMER
TRACK THE LENGTH OF TIME A MACHINE HAS BEEN OPERATING OR TO SHUT DOWN A PROCESS AFTER AN ACCUMULATIVE TIME PERIOD, RECURRING FAULTS.
RESET INSTRUCTION
RESET TIMER, COUNTER ACCUMULATED VALUES.
COUNT UP INSTRUCTION
COUNT THE NUMBER OF OPERATIONS OR PRODUCTS PRODUCED BY A SYSTEM.
COUNT DOWN INSTRUCTION
KEEP TRACK OF THE NUMBER OF ITEMS INVOLVED IN A SUBPROCESS.
MECHANICAL SYSTEM
PRIMARY SYSTEM, POWER TRANSMITTED THROUGH GEARS, BELTS, CHAINS, SHAFTS, COUPLINGS AND LINKAGES.
INFORMATIONAL SYSTEM
PRIMARY SYSTEM, MONITORS OPERATIONS, DISPLAYS QUANTITIES AND INDICATES STATUS OF MACHINES AND PROCESSES.
