Overview
The Allen-Bradley 1745-LP151 is a SLC 150 series processor unit designed for programmable logic control in industrial automation and process control applications. Part of Rockwell Automation’s early PLC product line, this 32-point processor unit was discontinued in 2014 but remains widely used in legacy manufacturing systems. The 1745-LP151 /C is compatible with existing SLC 100/150 controller platforms and is commonly specified for machine automation, motion control, and sequential logic applications.
Key Features
- 32-point I/O configuration: 20 sinking inputs, 10 triac outputs, 2 relay outputs
- CMOS RAM memory: 1200 words user memory with standard capacitor back-up and optional battery back-up
- Fast scan time: 4 msec scan time ensures responsive control and real-time processing
- LED indicators for fault diagnosis and run status monitoring
- High-speed input capability: With its High Speed Input (HSI) module, the SLC 150 processor unit can count high speed input signals (up to 5KHZ)
- Modular expansion support: Expansion unit can connect to the processor unit and to other expansion units through the ribbon cable; additional extensions can be made to increase the number of the I/O of the PLC up to 112
Technical Specifications
Voltage and Power:
Input voltage: 85-132/170-265 VAC at 50/60 Hz
Triac output: 85-265 VAC; Relay outputs: 10-250 VAC / 10-125 VDC
Memory and Processing:
Memory type: CMOS RAM; User memory size: 1200 words; Scan time: 4 msec
Environmental Ratings:
Operating temperature: 0 to 60°C; Storage temperature: -40 to 85°C; Humidity: 5 to 95% (without condensation)
Vibration: 0.015 inch peak to peak displacement, 2.5g peak (max) acceleration, 1 hr/axis
Typical Applications
The 1745-LP151 processor is well-suited for:
- Machine automation and sequential control in manufacturing environments
- Legacy system maintenance and retrofit projects where SLC 150 compatibility is required
- Small to mid-range automation with up to 112 I/O points (using expansion modules)
- Process control applications requiring reliable CMOS RAM with battery backup
- High-speed counting and pulse input applications via optional HSI modules
Compatibility & Replacements
The 1745-LP151 uses optional 1745-M1 EEPROM memory module to store program or load program for future back-up. Pocket programmer, interface converter or timer counter access terminal (1745-tcat) can be plugged in communication socket for programming this controller.
This unit is compatible with SLC 500 range; this controller being part of the SLC 150, has quite some advantages over the SLC 100 series as it comes with higher number of embedded IOs. For modern replacements, Rockwell Automation offers CompactLogix or ControlLogix processors, though direct 1:1 program migration requires careful evaluation of I/O counts and logic requirements.
