Allen-Bradley 1747-L542 SLC 500 RS-232 DH Controller

The Allen‑Bradley 1747-L542 SLC 500 RS-232 DH Controller is a SLC 5/04 CPU in the SLC 500 modular family, delivering 32K words of memory for program and data storage in a compact backplane-based module. It provides a built‑in RS‑232 programming port and a DH+ (Data Highway Plus) port for DH+ networking with other SLC 500 devices and HMIs. The unit supports a single local I/O chassis with up to 30 I/O slots, making it suitable for small-scale automation tasks. Backplane current draw is up to 1.0 A at 5 V DC and 200 mA at 24 V DC. The operating temperature range is 0 to 60 C (32 to 140 F). Common applications include simple machine control, process steps, and interfacing with RS-232 programming devices or DH+ networked devices in legacy control systems.