Description

Application Scenarios

Picture a regional bottling plant where the original SLC 5/01 controller could handle start/stop sequencing but struggled with the temperature-regulation loop on the pasteurizer. The engineering team upgraded the processor to the 1747-L524 without replacing a single I/O module or rewiring the panel. Suddenly the ladder logic could run a native PID instruction on the pasteurizer temperature, use indexed addressing to manage a small recipe table, and communicate over DH-485 to the line’s PanelView HMI and a small SCADA node — all within the same 4K memory envelope and the same single chassis slot . The upgrade took a weekend and extended the useful life of the control system by well over a decade, at a tiny fraction of a platform migration.Now imagine a municipal water-treatment plant whose pump-control panels have run reliably on SLC 500 hardware since the late 1990s. When the installed 1747-L524 fails after 25 years, the plant cannot justify a full PLC migration — the ladder logic is proven, the I/O wiring is mature, and the operators know the PanelView screens by heart. A certified refurbished 1747-L524 drops into the same slot 0, accepts the same 4K program from the archived RSLogix 500 project, and restores the pump sequencing, level control, and alarm logic without a single change to the application . The plant keeps its validated control scheme, avoids a six-figure migration, and returns to service inside a planned maintenance window.

Parameter

Main Parameters	Value / Description
Product Model	1747-L524 — Allen-Bradley catalog number for the SLC 5/02 processor; Series A, B, and C revisions exist
Manufacturer	Allen-Bradley / Rockwell Automation (USA) — a global leader in industrial automation and PLC systems
Product Category	PLC processor / CPU module, SLC 500 modular controller family, processor class SLC 5/02
User Memory	4K words (4,000 instructions), battery-backed RAM; optional EEPROM modules preserve RAM contents across power cycles
Backup Battery	1747-BA user-replaceable lithium battery, ~2 year typical life; must be replaced with chassis power ON to avoid memory loss
Max. Discrete I/O	4096 inputs / 4096 outputs — covers machine-level and small process-control applications
Max. Local Analog I/O	480 points (local); supports analog, digital, scanner, specialty, and intelligent I/O modules
Chassis / Slot Capacity	Up to 3 local chassis, 30 I/O slots total; processor occupies a single slot in a 1746 chassis
Communication	Built-in DH-485 (receive and initiate); RS-232 programming port; DF1 full- or half-duplex; ASCII; DH+ receive-only via 1785-KA5 bridge
Programming	RSLogix 500 (V1.00 or later), SLC 500 A.I. Series, APS; programming requires the 1747-PIC interface (or 1747-KE / 1784-KTx)
Program Scan Time	4.8 ms/K (typical for a 1K program of simple logic plus communication; actual depends on program size, instructions, and protocol)
I/O Scan Time	1.6 ms (typical); bit execution (XIC) 2.4 µs
Backplane Current	350 mA @ 5 V DC / 105 mA @ 24 V DC — must be included in the 1746 power-supply load calculation
Scan Hold-Up Time	20 ms to 3 s after loss of power (dependent on power-supply loading)
Instruction Set	71 instructions including PID, indexed addressing, process interrupts, 32-bit signed math, user fault routine, MSG messaging, FIFO/LIFO
Incompatible Modules	Does not support 1746-BLM and 1746-MPM modules
Supported Networks	DeviceNet, ControlNet, and Universal Remote I/O scanner modules; Remote I/O to 4096 I/O
Status Indication	Front-panel LEDs: Run, CPU Fault, Forced I/O, I/O fault, Battery Low, COMM
Environmental Adaptability	Operating 0 °C to +60 °C; storage −40 °C to +85 °C; humidity 5–95% non-condensing; operating shock 30 G; vibration 0.015 in p-p @ 5–57 Hz, 2.5 G @ 57–2000 Hz
Noise Immunity / Certification	Meets NEMA ICS 2-230; UL, cUL, CE, C-Tick; open-style (IP20 cabinet) enclosure
Physical Dimensions / Weight	145 × 35 × 142 mm (5.5 × 1.4 × 5.7 in); approx. 0.60 kg (1.31 lb) — compact single-slot footprint
Lifecycle Status	Discontinued January 31, 2017; functional replacement is the 1746 SLC system / CompactLogix migration; available as new-surplus or certified refurbished stock