PLC Troubleshooting & Maintenance.pdf
- 2. Senses Brain Motion Energy Manual Work Human Lags: • Cannot Work 24 Hours • Cannot work with 100% Accuracy & precision • Efficiency decreases as energy decreases Human nfi
- 3. Sensors Controllers Actuators Energy Automatic Work Machine Advantages: • Accuracy • No idle Time • More Production Lags: • Regular Troubleshooting & Maintenance nfi
- 4. What is Controllers? Controller A closed Loop Control System Controller is a part of Automatic Control System, which process the signal from sensors & send it to the actuators Sensors Actuator nfi
- 5. This is a PLC Input Terminals Output Terminals Programming Cable A/D Card D/A Card RS 485 nfi
- 6. This is a PLC Output Terminals Programming Cable Power 24 VDC Battery Input Terminals nfi
- 7. Output Terminals Programming Cable Power 24 VDC Input Terminals This is a PLC nfi
- 10. How to Select a PLC? Step 1: Selecting the Inputs - Number of Inputs - Input Types – NPN or PNP - Nature of Inputs– Digital or Analog - Voltage rating of the Inputs Step 2: Selecting the Outputs - Number of Outputs - Nature of Outputs – Digital or Analog - Voltage rating of the Inputs Step 3: Length of Program – Big or Small Nature of Program – Ladder Logic, SFC, Instruction List, FDB nfi
- 11. Programming Languages Ladder Logic SFC Instruction List FDB nfi
- 13. Common Industrial Hardware Representing the Binary Concept nfi
- 15. Bits – Nibble - Byte –Word Unlike English, computers have only two characters available 1 or 0. Each 1 or 0 is called a binary digit or bit. Binary is base or radix 2 Basics of Machine Language nfi
- 17. Digital Inputs & Outputs Typical Digital Input/ Output Signals • 12 VDC • 24 VDC • 120 VAC • 240 VAC nfi
- 18. Analog Inputs Typical analog signals come from temperature, pressure, position, and motor speed. Analog input modules convert analog signals to digital words. Analog input signals are current or voltage. Typical Analog input signals 0 to 10 volts DC -10 to +10 volts DC 0 to 5 or 1 to 5 volts DC 4 to 20 milliamps 0 to 20 milliamps -20 to +20 milliamps PLC INPUTS & OUTPUTS nfi
- 19. Connections from Field Devices Image courtesy of Allen-Bradley, a Rockwell Automation business PLC INPUTS & OUTPUTS nfi
- 20. Differential Analog Input Connections Image courtesy of Allen-Bradley, a Rockwell Automation business PLC INPUTS & OUTPUTS nfi
- 21. Analog Outputs Typical analog signals are required by Servo Valves, VFD’s, Servo Motors, Meters Analog Output modules convert Digital bits to analog signal. Analog Output signals are current or voltage. Typical Analog Output signals 0 to 10 volts DC -10 to +10 volts DC 0 to 5 or 1 to 5 volts DC 4 to 20 milliamps 0 to 20 milliamps -20 to +20 milliamps PLC INPUTS & OUTPUTS nfi
- 22. PLC Enclosure & System Components NEMA – 12 National Electric Manufacturer Association, USA nfi
- 23. PLC Enclosure Prevents: Dust Water Oil Mostly used for Indoor applications of automation. Some examples are Packaging Material handling Non-corrosive process control. NEMA enclosures are available in sizes from small wall mounts to multi-door freestanding models. nfi
- 25. Placement of PLC Components All Controller components should be mounted in a vertical (upright) position. To allow maximum cooling nfi
- 26. Duck & Wire Layout Keep AC signals separate from DC Signals DC Signals - I/O lines, such as TTL and analog AC Signals - Incoming Line Wires Minimizes the possibility of electrical noise pickup. nfi
- 28. POWER REQUIREMENTS Typical Power Requirement 220 VAC nfi
- 29. SAFETY CIRCUITRY Pull Rope Switch Door Switch Emergency Switch Automation Studio nfi
- 30. Master or Safety Control Relays Automation Studio nfi
- 31. PLC FAULT CONTACT PROTECTION Automation Studio nfi
- 32. PLC Maintenance HEAT, DUST & NOISE REGULATION nfi
- 33. HEAT & DUST REGULATION Temperature Withstand Range 0 ~ 60°C PLC MAINTENANCE nfi
- 34. NOISE REGULATION Shielded Cables for better communication PLC MAINTENANCE nfi
- 35. NOISE GENERATING DEVICES VARIABLE FREQUENCY DRIVES MOTOR STARTERS RELAYS AND CONTACTORS SOLENOIDS PLC MAINTENANCE nfi
- 36. NOISE FROM GROUNDING PLC TROUBLESHOOTING 2 nfi
- 37. PLC I/O Installation, Wiring & Precautions nfi
- 38. I/O INSTALLATION, WIRING, AND PRECAUTIONS I/O MODULE INSTALLATION Placement and installation of the I/O modules is simply a matter of inserting the correct modules in their proper locations. This procedure involves verifying the type of module (220 VAC/ 24 VDC output, 220 VDC/ 24 VDC input, etc.) and the slot address as defined by the I/O address assignment document. Each terminal in the module is then wired to the field devices that have been assigned to that termination address. The user should remove power to the modules (or rack) before installing and wiring any module.11 nfi
- 39. I/O INSTALLATION, WIRING, AND PRECAUTIONS WIRING WIRE SIZE CONSIDERATION nfi
- 40. I/O INSTALLATION, WIRING, AND PRECAUTIONS WIRE SIZE CONSIDERATION nfi
- 41. I/O INSTALLATION, WIRING, AND PRECAUTIONS WIRE LABELLING nfi
- 42. I/O INSTALLATION, WIRING, AND PRECAUTIONS WIRE BUNDLING nfi
- 44. PLC START-UP AND CHECKING PROCEDURES Model numbers Placement Power Supply Inspection Verify Field Wiring & I/O comm. cables nfi
- 45. STATIC INPUT/ OUTPUT WIRING CHECK Output Terminals Input Terminals nfi
- 47. PLC PREVENTIVE MAINTENANCE Regular Filter Cleaning Regular Dusting Dust restricts heat dissipation Avoid Conductive Dust I/O Module Check for any Loose connections Avoid Noise generating Equipment close to PLC Avoid documentation to create HOT SPOT Install vibration Detector in area of high vibration nfi
- 50. Is Power Indicator Lit? POWER LED IS TURNED OFF Is power supply operating? Supply the power Does the power LED turned on? Is the fuse blown? Is the power Supply cable Connected? Is the voltage within the rated power? Over current Device activated? Does the power LED turned on? Does the power LED turned on? Does the power LED turned on? See the power supply within 180 ~ 240 VAC Replace the Fuse Connect the power supply properly Eliminate excess current & switch power ON/OFF Does the power LED turned on? Write the steps & Contact customer care COMPLETE NO YES YES YES NO NO NO NO NO NO YES NO NO NO YES YES YES YES YES YES nfi
- 51. RUN Indicator not Lit RUN INDICATOR NOT LIT Is the ERR/ALM Indicator Lit? Turn the power supply OFF & then ON again Is a fatal error Displayed? Is PC mode displayed On Programming device? Is the RUN Indicator lit? Determine the cause of the error with the Programming device Switch to RUN or MONITOR mode Identify the error, eliminate its cause, & clear the error. Replace the CPU Unit NO NO NO NO NO YES YES YES YES YES Is PC mode Displayed on Programming Device? END FATAL ERROR CHECK nfi
- 52. Program cannot be written PROGRAM CANNOT BE WRITTEN TO PLC Is the mode setting Switch set to the remote stop? Switch to the remote STOP mode & execute the program mode Is ERR LED Blinking? After reading error code by using peripheral device, correct the content COMPLETE NO NO YES NO nfi
- 53. ENVIRONMENT CONDITION CHECK Environment Condition Check Is the ambient temperature below 55 degree? Consider using a FAN or COLLER Is the ambient temperature above 0 degree? Consider using a HEATER END Is the ambient humidity between 10% ~ 85% Consider using an air conditioner Is noise being controlled? Install surge protectors or other noise reducing equipment at noise sources Is the installation environment ok? Consider constructing an instrument panel or cabinet NO NO NO NO NO YES YES YES YES YES nfi
- 54. ERR/ALM INDICATOR FLASHING ERR/ALM Indicator flashing Determine the cause of the error with a programming device IS a non fatal error Indicated? Identify the error, eliminates its cause & clear the error Replace the CPU Unit NO NO YES NON- FATAL ERROR CHECK Is the ERR/ALM Indicator flashing? END FLASHING nfi
- 55. I/O CHECK MALFUNCTIONING OF SOL 1 Check the voltage at IR 01003 terminals Is the Output wiring correct? Check output device SOL 1. Operation ok? Replace the CPU Unit, Expansion Unit, or Expansion I/O Unit with the problem Is the IR 01003 output Indicator operating? Wire correctly Correct the short circuit or limit the connected load to the specified range Monitor the ON/OFF status of IR 01003 with the Programming Device Is the external power supply Shorted or overload? Disconnect the external wires & check the conductivity of each wire Operation ok? Operation ok? NO YES YES YES YES YES YES NO NO NO NO NO 0002 0003 SOL 1 01003 01003 Next slide nfi
- 56. I/O CHECK Check the voltage at the IR 0002 & IR 0003 terminals Operation ok? Replace the CPU Unit, Expansion Unit, or Expansion I/O Unit with the problem Are the IR 0002 & IR 0003 Input indicators operating Normally? Is the wiring correct? Wire Correctly Operation ok? Are the terminals screws loose? NO YES 0002 0003 SOL 1 01003 01003 Replace the CPU Unit, Expansion Unit, or Expansion I/O Unit with the problem Check operation by using a dummy input signal to turn the input ON & OFF Check input devices LS1 & LS2 Check the voltage at the IR 0002 & IR 0003 terminals Operation ok? Return to Start Tighten the terminal screws From previous slide NO NO NO NO NO YES YES YES YES nfi