Comprehensive Guide to Rockwell (Allen-Bradley) PLC Seri

Comprehensive Guide to Rockwell (Allen-Bradley) PLC Seri

1. SLC 500 Series (1746 / 1747) — Classic Mid-range System 3

• Positioning: This was the most successful modular PLC of the 1980s and 90s4. Although it is currently in the end-of-life or maintenance phase, its massive installed base makes it critical for maintaining legacy equipment5.
  
  

• Core Model List6:
  
  

• Processors (1747): 1747-L532 (SLC 5/03), 1747-L541 (SLC 5/04), and 1747-L551 (SLC 5/05 with Ethernet port)7.
  
  

• Digital I/O (1746): 1746-IB16 (24V DC Input), 1746-IA16 (120V AC Input), 1746-OW16 (Relay Output), and 1746-OB32 (32-point high-density output)8.
  
  

• Analog I/O (1746): 1746-NI4 (4-channel input), 1746-NO4I (4-channel current output), and 1746-FIO4I (mixed I/O)9.
  
  

• Accessories: 1746-P2 (Power Supply) and 1746-A10 (10-slot chassis)10.
  
  

• Applicable Equipment: Conveyor belt control, simple packaging machines, independent pump stations, and legacy injection molding machines11.
  
  

• Industry Example: Food Processing Plants12. It is used to control legacy filling lines or simple material handling systems, primarily handling discrete logic and minor temperature monitoring13.
  
  

• Positioning: A top-tier PAC (Programmable Automation Controller)15. It supports high performance, high point counts, hot-swapping, redundancy, and extremely complex motion control (CIP Motion)16.
  
  

• Core Model List17:
  
  

• Processors (L8 Series): 1756-L81E, 1756-L83E, and 1756-L85E (Memory increases with model number; L8 series includes built-in Gigabit Ethernet)18.
  
  

• Communication Modules: 1756-EN2T (Standard Ethernet bridge), 1756-EN4TR (Supports Dual-port Ring), and 1756-RM2 (Redundancy module)19.
  
  

• Digital I/O: 1756-IB16I (Isolated input), 1756-OB32 (32-point DC output), and 1756-IA16I (AC input)20.
  
  

• Analog I/O: 1756-IF16 (16-channel input), 1756-OF8 (8-channel output), and 1756-IRT8I (RTD/Thermocouple)21.
  
  

• Accessories: 1756-A7/A17 (Chassis) and 1756-PA72/PB72 (AC/DC Power Supplies)22.
  
  

• Applicable Equipment: Large automotive assembly lines, multi-axis collaborative robots, plant-wide data schedulers, and refinery process control23.
  
  

• Industry Example: Automotive Manufacturing24. In welding shops, the 1756 manages coordination for hundreds of robots, safety interlocks, and high-speed data exchange with MES systems25.
  
  

• Positioning: A "scaled-down" version of the 175627. It features a rackless design where modules connect via a side bus28. It is highly cost-effective and suitable for small-to-medium systems29.
  
  

• Core Model List30:
  
  

• Processors (L3 Series): 1769-L30ER, 1769-L33ER, and 1769-L36ERM (Supports servo motion control)31.
  
  

• All-in-one Controllers: 1769-L24ER-QB1B (Built-in 16DI/16DO)32.
  
  

• Digital I/O: 1769-IQ16 (16-point input), 1769-OW16 (Relay output), and 1769-IQ32 (32-point high-density input)33.
  
  

• Analog I/O: 1769-IF4 (4-channel input), 1769-OF4CI (Isolated current output), and 1769-IF8 (8-channel input)34.
  
  

• Accessories: 1769-AENTR (Ethernet adapter for remote I/O expansion) and 1769-ECR (Right-side end cap)35.
  
  

• Applicable Equipment: Labeling machines, medium-sized mixers, automated palletizers, and pharmaceutical packaging equipment36.
  
  

• Industry Example: Pharmaceutical Industry37. In an automated cartoning machine, the 1769 controls servo motors for high-speed picking and packaging, achieving high performance within a compact control cabinet38.
  
  

In a modern Tobacco Factory, you can find all three series operating together41:

1. Central Control Room (1756): Uses a 1756-L83E to centrally monitor production volume data and quality parameters for the entire line42.
   
   

2. Cigarette Making & Packaging Workshop (1769): Each high-speed cigarette machine is independently equipped with a 1769-L33ERM to handle high-precision cutter synchronization and servo control43.