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Programmable Logic Controllers. Day 2 Presentation Machine Design. Agenda. PLC System Design Process Machine Description PLC Selection Criteria PLC Initial System Selection Advantages of AC vs. DC # of I/O Type of I/O Team Management. PLC System Design Process. Machine Specifications
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Programmable Logic Controllers Day 2 Presentation Machine Design
Agenda PLC System Design Process Machine Description PLC Selection Criteria PLC Initial System Selection Advantages of AC vs. DC # of I/O Type of I/O Team Management Engineering Technology
PLC System Design Process Machine Specifications Machine I/O list Machine System Flowchart Machine Wiring – Lecture 10 Ladder Logic – Lecture 10 Test and Debug Final Documentation Engineering Technology
Machine Description - Specifications • Automated Drill Press • Cycle Specifics: • Operator places part in drill press • Operator pushes start push buttons • Part is clamped • Spindle motor turns on • Drill head drives down until it hits the lower limit switch • Drill head drives up until it hits the upper limit switch • Spindle turns off • Part is unclamped • Operator removes part. Engineering Technology
Machine Description - Specifications • Automated Drill Press • Startup Specifics: • Hydraulic pump runs for 15 seconds every 5 minutes • Emergency stop button halts all movement • Reset button changes state to startup state • Home button drives drill head up until the limit switch is set • Coolant pump runs while spindle motor is on • Light curtain fault halts all movement • Light tower: • Green – Cycle in Progress • Blue – Waiting for Operator • Red – Fault Engineering Technology
Machine Description – I/O List • Inputs: • Emergency-Stop • Reset • Master Start • Home • Cycle Start • Light Curtain • Part Clamped Limit Switch • Part Clamped Limit Switch • Drill Head Down Limit Switch • Drill Head Up Limit Switch Engineering Technology
Machine Description – I/O List • Outputs: • Hydraulic Pump • Spindle On • Coolant Pump • Drill Head On • Drill Head Direction • Light Tower - Green • Light Tower - Blue • Light Tower - Red Engineering Technology
PLC Selection Criteria PC or PLC? Number of I/O (memory also) Type of I/O Functions (PID, Recipes, Data Storage) Programming Language Redundancy Safety Standardization Price (Hardware and Complements) Reputation Engineering Technology
PLC Initial System Selection 40% extra space Fixed vs. Variable DC vs. AC Local vs. Multipoint Special Function Operator Interface Documentation 70% input 30% output Engineering Technology
Advantages of DC vs. AC Smaller Wires Less Insulation Smaller Conduit Smaller Switches Safety Smaller Connectors Engineering Technology
# of I/O Nano 8-32 MicroLogix Micro 32-250 CompactLogix Small 250-4k ControlLogix Medium 2k-16k Momentum (Mod) Large 8k-32k Quantum (Mod) Very Large >32k PLC-5 Engineering Technology
Type of I/O Remote I/O Networking Expandability Specialized I/O • High Speed Counters • Motion Control (PID) • Basic • Communications • TTL Digital I/O • RTD • Thermocouple Engineering Technology
Team Managment Electrical Engineer Mechanical Engineer Operator Engineering Technology
Diagnostics Level 1 – LED’s Level 2 – LCD, terminal Level 3 – Bidirectional Display Level 4 – PC Engineering Technology
Reason for Diagnostics Detect problems before they occur Reduce down time Quality control Program improvements Engineering Technology
Next Class! PLC Languages Engineering Technology