PLC2 Flashcards
IF THE VACUUM DOES NOT TURN ON AT STEP 2 OF THE SEQUENCE WHAT TWO I/O DEVICES SHOULD YOU CHECK TO DETERMINE IF ONE OF THESE DEVICES HAS FAILED?
MR2 OR SOL2A
WHAT IS THE LIKELY PROBLEM IF A PLC INPUT INDICATOR TURNS ON WHEN THE INPUT DEVICE IS ACTIVATED BUT THE ASSOCIATED INPUT INSTRUCTION IN THE PLC PROGRAM DOES NOT CHANGE STATE?
INPUT MODULE
WHAT BEST DESCRIBES THE PROCESS OF SYSTEM LEVEL TROUBLESHOOTING?
USING A METHODICAL SERIES OF TESTS TO ISOLATE THE PROBLEM TO A SPECIFIC COMPONENT
WHAT STEPS SHOULD BE TAKEN BEFORE TROUBLESHOOTING THE OPERATION OF AN INPUT DEVICE AND ITS INTERACTION WITH THE PLC PROGRAM?
DISABLE OUTPUTS IN PLC
WHICH TYPE OF FAILURE IS OFTEN EASIER TO TROUBLESHOOT BECAUSE IT AFFECTS THE ENTIRE PLC SYSTEM?
POWER DISTRIBUTION CIRCUIT
WHAT DOCUMENT IS USED BY PLC PROGRAM DEVELOPERS TO DETERMINE THE STATE OF A PLCS INPUTS AND OUTPUTS FOR EACH STEP IN A MACHINE SEQUENCE?
TRUTH TABLE
WHICH METHOD OF PLC TROUBLESHOOTING BEST DESCRIBES THE PROCESS OF CHECKING THE STATUS OF SERIES OF INPUT INSTRUCTION ON A RUNG ONE AFTER THE OTHER TO LOCATE THE INPUT THAT IS PREVENTING THE PROGRAM SEQUENCE ROM CONTINUING?
OUTPUT BACK
WHAT TRIGGERS THE START OF EACH STEP IN AN EVENT DRIVEN PLC SEQUENCE PROGRAM?
AN INPUT TRIGGERED BY THE COMPLETION OF THE PREVIOUS STEP
WHICH OF THE FOLLOWING IS NOT TYPICALLY USED TO TROUBLESHOOT A PLC PROCESSOR?
PLC SOFTWARE
WHAT IS MOST LIKELY FAULTED IN A PLC SYSTEM IF A PLC OUTPUT INSTRUCTION IS ON IN THE LOGIC PROGRAM AND CONTROL POWER IS ON BUT THERE IS NO OUTPUT VOLTAGE AT THE OUTPUT TERMINAL?
OUTPUT POINT ON THE OUTPUT MODULE BAD
IF A MACHINE HAS STOPPED IN THE MIDDLE OF ITS SEQUENCE UNEXPECTEDLY AND ALL THE INDICATORS ON THE PLC ARE NORMAL WHERE IS THE PROBLEM LIKELY LOCATED?
I/O FIELD DEVICES
IF A PLC INPUT INDICATOR ARE CORRECT BUT EXPECTED OUTPUTS ARE NOT PRODUCED WHAT IS THE FIRST STEP TO TROUBLESHOOT THE PROBLEM?
VERIFY THAT THE CONTROLLER IS IN RUN MODE
IF A PLCS INPUT INDICATORS ARE CORRECT BUT EXPECTED OUTPUTS ARE NOT PRODUCED WHAT IS THE FIRST STEP TO TROUBLESHOOT THE PROBLEM?
VERIFY THAT THE PROCESSORS FORCE INDICATOR IS OFF
WHAT IS THE FIRST CHECK YOU SHOULD MAKE IF A MACHINE SUDDENLY FAILS ALL PLC INDICATORS ARE NOW OFF AND THE OTHER MACHINES IN THE AREA ARE STILL OPERATING?
CHECK THE MAIN POWER DISCONNECT
WHEN ARE I/O FORCES FIRST APPLIED IN A PLC?
USER MUST CONFIRM THE FORCES BEFORE THEY ARE APPLIED
WHAT IS THE NEXT CHECK YOU SHOULD MAKE TO TROUBLESHOOT THE PROBLEM IF A PLC INPUT INDICATOR DOES NOT TURN ON AND OFF WHEN THE INPUT DEVICE IS OPERATED?
MEASURE SIGNAL AT INPUT MODULE TERMINAL WHEN INPUT DEVICE IS OPERATED
THE OUTPUT TAG FILE AND ——ARE NOT CHANGED WHEN A FORCE OUTPUT IS APPLIED.
PROGRAM
THE SYMPTOMS OF AN INTERNALLY SHORTED MODULE MAKE IT APPEAR AS IF THERE IS A ——— PROBLEM.
POWER SUPPLY
THE PLC SYSTEMS REQUIRES———–POWER TO OPERATE THE PROCESSOR, I/O, AND OTHER CONNECTED MODULES.
DC
STEP 1 IN TESTING DISCRETE INPUT DEVICE IS TO ——–THE SYSTEM.
DISABLE
FORCING ON A PLC OUTPUT WHICH IS ASSOCIATED WITH THE PLCS LOGIC PROGRAM COULD AFFECT ALL OF THE FOLLOWING EXCEPT?
PROCESSOR STATE
WHAT IS THE LIKELY PROBLEM ONLY ONE CYCLE AFTER PB1 IS MOMENTARILY PRESSED TO START THE SEQUENCE?
SOL 2A IS FAULTED OPEN
AT WHICH TEST POINT WOULD YOU FIRST TAKE VOLTAGE MEASUREMENT IF ONE OR MORE OUTPUT MODULE INDICATOR LIGHTS ARE ON BUT THE ASSOCIATED OUTPUT DEVICES ARE NOT ON?
TP5
WHICH OF THESE IS NOT REQUIRED BEFORE FORCING ON A PLC OUTPUT TO TEST AN OUTPUT DEVICE?
LOGIC PROGRAM
WHICH OF THESE INDICATORS TURNS SOLID GREEN WHEN THE PLC PROCESSOR IS SUCCESSFULLY EXECUTING ITA PROGRAM?
RUN
WHICH COMPONENT IS MOST LIKELY FAULTED IF THE SEQUENCE FAILS TO START AFTER PB1 IS ACTIVATED?
SOL 2A
WHAT IS MOST LIKELY TO SUPPLY POWER TO THE DC ELECTRONIC SENSORS WIRED TO PLC DISCRETE INPUT?
EXTERNAL POWER SUPPLY
WHAT DOCUMENT LISTS THE ACTIONS THAT A MACHINE MAKES TO PERFORM ITS FUNCTION?
SEQUENCE OF OPERATIONS
IN THIS LOGIC PROGRAM CONTROLLING A PLASTIC INJECTION MOLDING MACHINE WHAT INSTRUCTION AND ADDRESS WOULD YOU PLACE INTO PROGRAM TO REPLACE THE SHADED BLOCK MARKED A ON THE LAST RUNG TO MAKE THE PROGRAM PERFORM THE SEQUENCE GIVEN?
NORMALLY CLOSED INSTRUCTIONS, ADDRESS: D13
WHICH TROUBLESHOOTING METHOD CAN ELIMINATE THE NEED TO TEST A LARGE PORTION OF A SYSTEM WITH ON TEST?
HALF SPLIT
IF THE CLAMP AND DRILL MACHINE SHOWN HAS STOPPED UNEXPECTEDLY AFTER PERFORMING STEP 1 OF ITS SEQUENCE WHAT ARE THE MOST LIKELY I/O DEVICES FAILURES?
LS3, SOL1A
WHAT IS THE LIKELY PROBLEM IF THE MEASURED VOLTAGE AT THE PLC OUTPUT TERMINAL CHANGES FROM LOW TO HIGH WHEN THE OUTPUT IS FORCED ON BUT THE OUTPUT DEVICE DOES NOT RESPOND?
OUTPUT DEVICE OR WIRING IS BAD
IN A PREVIOUSLY WORKING PLC SYSTEM WHICH OF THESE PROBLEMS WILL NOT APPEAR AS A PROCESSOR FAULT PR FAULT MESSAGE?
I/O FIELD DEVICE FAILURE
WHICH COMPONENT IS MOST LIKELY FAULTED IF THE DRILL CYLINDER EXTENDS AND NOT RETRACT?
LS2
WHAT IS THE MOST LIKELY PROBLEM IF A PLCS OUTPUT INDICATOR IS ON AND THE OUTPUT DEVICE TO WHICH IT IS WIRED IF OFF?
OUTPUT DEVICE IS BAD
AT WHICH TEST POINT WOULD YOU FIRST TAKE VOLTAGE MEASUREMENT IF ALL OF THE INDICATOR LIGHTS ON THE INPUT MODULE ARE OFF AND YOU FIND THESE ADDITIONAL CONDITIONS: MAIN POWER SWITCH IS SWITCHED ON, CONTROL POWER PUSH BUTTON HAS BEEN PRESSED, AND PLS POWER SUPPLY INDICATOR IS ON?
TP4
