Texas Instruments System 505 Modular PLC Platform (525‑110, 525‑1102, 505‑6660, 4516, 4832, 4332)

The Texas Instruments System 505 is a classic, highly modular programmable logic controller (PLC) platform widely deployed in heavy industrial applications. This specific configuration includes the 525‑110 CPU, the 525‑1102 expansion interface, the 505‑6660 power supply, and a selection of I/O modules: 4516 (16‑point digital input), 4832 (32‑point digital output), and 4332 (analog input). The system is renowned for its ruggedness, hot‑swap capability, and support for remote I/O networks.

Model 525‑110 CPU

The 525‑110 is the central processor unit for System 505, featuring a 16‑bit microprocessor running at 10 MHz. Program memory: 128 Kwords of CMOS RAM (battery‑backed) or EPROM. Execution speed: 0.5 µs per basic bit instruction. The CPU supports up to 1024 digital I/O points and 256 analog I/O channels locally, expandable via remote bases. Programming is done via TISOFT software (DOS‑based) or Workshop 505 (Windows) using ladder logic, structured text, or sequential function charts. The CPU includes two RS‑232C/RS‑422 ports for programming and SCADA communication.

Model 525‑1102 Expansion Interface

The 525‑1102 is an expansion interface module that connects the main CPU rack to additional I/O racks via a shielded twisted‑pair cable (up to 300 meters). It supports four remote bases, each with up to 16 I/O slots. The module has built‑in diagnostics for communication errors and an LED status indicator. It operates transparently to the user program, automatically refreshing I/O data every scan.

Model 505‑6660 Power Supply

The 505‑6660 is a high‑capacity power supply for the System 505 backplane. Input: 120/240 V AC (switch‑selectable) or 24 V DC. Output: 5 V DC at 20 A, 24 V DC at 4 A (for internal I/O power). It provides short‑circuit and overvoltage protection. The supply features a front‑panel ON/OFF switch, LED power indicator, and a battery backup circuit for CPU memory (battery not included). Operating temperature range: 0‑60 °C.

I/O Modules: 4516, 4832, 4332

The 4516 is a 16‑point digital input module, 24 V DC sink/source, optically isolated, with 4 ms filter time. The 4832 is a 32‑point digital output module (transistor, 0.5 A per point, 24 V DC), ideal for high‑density solenoid control. The 4332 is an 8‑channel analog input module (0‑10 V or 4‑20 mA, 12‑bit resolution), used for process variables. All modules mount on the 505 backplane and support hot swapping under certain conditions.

Communication and Networking

System 505 supports Siemens H1 (Ethernet), Profibus DP, and TIWAY I (RS‑485) networks using dedicated communication modules (e.g., 505‑CP5432 for Ethernet). The 525‑110 CPU also supports the proprietary TI Native protocol for high‑speed peer‑to‑peer communication between multiple PLCs.

Applications

This PLC system is typically found in mining, oil & gas, steel mills, and water treatment plants. Its modularity allows gradual upgrades, while the ability to run legacy TISOFT software makes it attractive for maintaining older installations without full replacement.