Purchase now: Allen Bradley 1747-L511 SLC 5/01 Processor
Purchase now: Atlantechdrives provides you the 1747-L511, the foundational CPU processor that launched the legendary Allen Bradley SLC 500 automation family. Classified as an SLC 5/01 controller, this unit is designed for basic, high-reliability machine control applications where simplicity and endurance are prioritized over complex mathematics or high-level network integration. Equipped with 1K of fixed instruction memory, the 1747-L511 is the perfect replacement processor for legacy equipment such as standalone packaging wrappers, simple conveyor sorters, and standalone pump controllers that have been running flawlessly since the 1990s. By replacing a failed 5/01 with an exact 1747-L511 match, you avoid the costly engineering time required to migrate a legacy program to a modern controller platform.
Technical Specifications of the 1747-L511
The 1747-L511 mounts in slot 0 of any 1746 chassis. It features a single RJ45 port dedicated to the DH-485 communication protocol for programming and HMI integration, and relies entirely on the chassis backplane for its 5V DC power.
- Part Number: 1747-L511
- Processor Class: SLC 5/01 CPU
- Total User Memory: 1K Words (Instructions and Data)
- Communication Port: DH-485 via RJ45 jack
- Maximum Local I/O Capacity: 3940 inputs / 3940 outputs
- Maximum Local Chassis: 3 (Up to 30 slots total)
- Programming Software: RSLogix 500 or legacy APS/AI software
- Backplane Current Draw: 350 mA at 5V DC, 105 mA at 24V DC
Expert Installation Advice: The RJ45 Ethernet Hazard
The single most catastrophic mistake made during the installation or troubleshooting of an SLC 5/01 processor involves its communication port. Expert Tip: The DH-485 port on the front of the 1747-L511 utilizes a standard 8-pin RJ45 modular jack. It is NOT an Ethernet port. This port carries 24V DC power to drive external interface modules (like the 1747-PIC or 1747-AIC). If a technician mistakenly plugs a standard Ethernet cable from a factory network switch or a laptop’s LAN port into the front of the 1747-L511, the 24V DC will instantly travel into the Ethernet equipment, permanently destroying the network card and potentially frying the processor port as well. Always use the specific 1747-C13 DH-485 cable and label the port clearly to prevent IT disasters.
Maintenance and Memory Limitations
When maintaining a machine controlled by a 1747-L511, you must be hyper-aware of its memory constraints. 1K of memory fills up incredibly quickly. Furthermore, the SLC 5/01 architecture does not support online editing. If you need to change a timer preset or add an interlock rung, you must physically stop the PLC, switch to program mode, download the entire revised logic file via your 1747-UIC USB adapter, and then switch the processor back to RUN mode. Always schedule downtime for even the most minor code alterations.
Frequently Asked Questions (FAQs)
Q: Does the 1747-L511 support PID loops for temperature control?
A: No. The SLC 5/01 processor does not support the advanced PID instruction set. If your machine requires PID closed-loop control, you must upgrade your processor to at least an SLC 5/02 (like the 1747-L524).
Q: How do I back up the program if the battery dies?
A: It is highly recommended to install an optional EEPROM memory module (like the 1747-M1) into the socket on the processor board. You can configure the CPU to automatically load the program from the EEPROM into RAM upon power-up, saving you from a dead battery wipe.
Do you need more references from this brand? Explore our full catalog of Allen Bradley here.
The SLC 5/01 processor is the entry-level brain for modular systems housed in the 1746-A4 compact chassis.
