Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

PLC Troubleshooting & Maintenance


Published on

Unlock full featured course with 250+ Video Lectures at 20% Discount for "Learn 5 PLC's in a Day" lifetime E-Learning course for 39 USD only:

Enroll for Advanced Industrial Automation Training with PLC, HMI and Drive Combo with 300+ Video Lecture for 69.3 USD only:

Published in: Education, Business

PLC Troubleshooting & Maintenance

  1. 1. PLC Troubleshooting & Maintenance nfi
  2. 2. Manual Work Brain Motion Senses Human Lags: • Cannot Work 24 Hours • Cannot work with 100% Accuracy & precision • Efficiency decreases as energy decreases Energy Human
  3. 3. Automatic Work Controllers Actuators Sensors Machine Advantages: • Accuracy • No idle Time • More Production Energy Lags: • Regular Troubleshooting & Maintenance
  4. 4. What is Controllers? Controller is a part of Automatic Control System, which process the signal from sensors & send it to the actuators Sensors Controller A closed Loop Control System Actuator
  5. 5. This is a PLC Input Terminals Output Terminals D/A Card Programming Cable A/D Card RS 485
  6. 6. This is a PLC Power 24 VDC Battery Input Terminals Programming Cable Output Terminals
  7. 7. This is a PLC Input Terminals Programming Cable Output Terminals Power 24 VDC
  8. 8. Understanding PLC
  9. 9. Understanding PLC
  10. 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: Step 3: Selecting the Outputs - Number of Outputs - Nature of Outputs – Digital or Analog - Voltage rating of the Inputs Length of Program – Big or Small Nature of Program – Ladder Logic, SFC, Instruction List, FDB
  11. 11. Programming Languages Ladder Logic SFC Instruction List FDB
  12. 12. PLC Ladder Logic
  13. 13. Common Industrial Hardware Representing the Binary Concept
  14. 14. Basics of Machine Language nfi
  15. 15. Basics of Machine Language 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
  16. 16. PLC Inputs & Outputs nfi
  17. 17. Digital Inputs & Outputs Typical Digital Input/ Output Signals • • • • 12 VDC 24 VDC 120 VAC 240 VAC
  18. 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. PLC INPUTS & OUTPUTS 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
  19. 19. PLC INPUTS & OUTPUTS Connections from Field Devices Image courtesy of Allen-Bradley, a Rockwell Automation business
  20. 20. PLC INPUTS & OUTPUTS Differential Analog Input Connections Image courtesy of Allen-Bradley, a Rockwell Automation business
  21. 21. Analog Outputs    PLC INPUTS & 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
  22. 22. Basics of PLC Programming Ladder Logic
  23. 23. PLC Enclosure & System Components NEMA – 12 National Electric Manufacturer Association, USA
  24. 24. 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.
  25. 25. Enclosure Layout
  26. 26. Placement of PLC Components To allow maximum cooling All Controller components should be mounted in a vertical (upright) position.
  27. 27. 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.
  28. 28. Power Requirement & Safety Circuitry
  29. 29. POWER REQUIREMENTS Typical Power Requirement 220 VAC
  30. 30. SAFETY CIRCUITRY Door Switch Pull Rope Switch Emergency Switch Automation Studio
  31. 31. Master or Safety Control Relays Automation Studio
  32. 32. PLC FAULT CONTACT PROTECTION Automation Studio
  33. 33. PLC Maintenance HEAT, DUST & NOISE REGULATION
  34. 34. PLC MAINTENANCE HEAT & DUST REGULATION Temperature Withstand Range 0 ~ 60°C
  35. 35. PLC MAINTENANCE NOISE REGULATION Shielded Cables for better communication
  38. 38. PLC I/O Installation, Wiring & Precautions
  39. 39. 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
  45. 45. PLC START-UP AND CHECKING PROCEDURES Model numbers Placement Power Supply Inspection Verify Field Wiring & I/O comm. cables
  46. 46. STATIC INPUT/ OUTPUT WIRING CHECK Input Terminals Output Terminals
  48. 48. 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
  51. 51. POWER LED IS TURNED OFF Is Power Indicator Lit? NO Is power supply operating? Supply the power NO YES NO Is the voltage within the rated power? Is the fuse blown? Does the power LED turned on? YES NO NO YES Does the power LED turned on? YES Does the power LED turned on? Eliminate excess current & switch power ON/OFF NO Write the steps & Contact customer care YES Connect the power supply properly NO YES Over current Device activated? YES Replace the Fuse NO Is the power Supply cable Connected? YES See the power supply within 180 ~ 240 VAC NO YES Does the power LED turned on? NO Does the power LED turned on? YES COMPLETE
  52. 52. RUN Indicator not Lit RUN INDICATOR NOT LIT NO YES Is the ERR/ALM Indicator Lit? Is PC mode Displayed on Programming Device? YES NO Determine the cause of the error with the Programming device Is PC mode displayed On Programming device? NO Turn the power supply OFF & then ON again YES Is a fatal error Displayed? YES Identify the error, eliminate its cause, & clear the error. NO Switch to RUN or MONITOR mode Is the RUN Indicator lit? YES END NO Replace the CPU Unit FATAL ERROR CHECK
  53. 53. Program cannot be written PROGRAM CANNOT BE WRITTEN TO PLC Is the mode setting Switch set to the remote stop? NO Switch to the remote STOP mode & execute the program mode YES NO Is ERR LED Blinking? NO COMPLETE After reading error code by using peripheral device, correct the content
  54. 54. Environment Condition Check Is the ambient temperature below 55 degree? NO ENVIRONMENT CONDITION CHECK Consider using a FAN or COLLER YES Is the ambient temperature above 0 degree? NO Consider using a HEATER YES Is the ambient humidity between 10% ~ 85% NO Consider using an air conditioner YES NO Is noise being controlled? Install surge protectors or other noise reducing equipment at noise sources YES NO Is the installation environment ok? YES END Consider constructing an instrument panel or cabinet
  55. 55. ERR/ALM INDICATOR FLASHING ERR/ALM Indicator flashing Determine the cause of the error with a programming device IS a non fatal error Indicated? YES Identify the error, eliminates its cause & clear the error NO Is the ERR/ALM Indicator flashing? FLASHING NO Replace the CPU Unit END NON- FATAL ERROR CHECK
  56. 56. 0002 MALFUNCTIONING OF SOL 1 0003 01003 SOL 1 I/O CHECK 01003 NO Is the IR 01003 output Indicator operating? YES Wire correctly Operation ok? Correct the short circuit or limit the connected load to the specified range NO NO Monitor the ON/OFF status of IR 01003 with the Programming Device Is the Output wiring correct? YES YES Is the external power supply Shorted or overload? YES Operation ok? YES NO Disconnect the external wires & check the conductivity of each wire YES Check output device SOL 1. Operation ok? NO Replace the CPU Unit, Expansion Unit, or Expansion I/O Unit with the problem NO Next slide Check the voltage at IR 01003 terminals
  57. 57. 0002 0003 01003 SOL 1 I/O CHECK From previous slide 01003 Are the IR 0002 & IR 0003 Input indicators operating Normally? NO Check the voltage at the IR 0002 & IR 0003 terminals YES Check the voltage at the IR 0002 & IR 0003 terminals Operation ok? Operation ok? YES NO NO YES Check operation by using a dummy input signal to turn the input ON & OFF YES Is the wiring correct? YES Are the terminals screws loose? NO NO Wire Correctly Tighten the terminal screws NO Operation ok? Replace the CPU Unit, Expansion Unit, or Expansion I/O Unit with the problem Check input devices LS1 & LS2 Return to Start Replace the CPU Unit, Expansion Unit, or Expansion I/O Unit with the problem
  58. 58. 100+ Video Tutorials Coupon Code in $99 $49 Life time Access Course Outline Learn to Code | Code to Learn nfi Learn 4 PLC’s in a Day presents PLC – Programmable Logic Controller Delta DVP 14 SS + 16 SP • 100+ PLC Video Tutorials Allen Bradley M1000 • Doubt Clearing Complementary LIVE Sessions on Team Viewer Siemens S7 200 • Ladder Logic Programming Schneider • PLC Presentations, PLC Circuits, PLC Codes Analog Cards Programming • FREE PLC Simulation Software for Practice 04 AD – Analog to Digital 04DA- Digital to Analog For more courses visit
  59. 59. PLC & VFD Advanced Course 4 PLC’s Training Platforms $149 Course Link: Course Highlights: • 30 Live Practical Classes on PLC, Analog Cards & AC drives- VFD • 100+ PLC Video Tutorials with Lifetime Access & FREE PLC Simulator • FREE Circuits Diagram For more courses visit
  60. 60. Thanks nfi