CTI 2512 75-Watt AC/DC Power Supply for CTI 2500 and Simatic 505 Series PLCs

The CTI 2512 is a 75W power supply module designed to power CTI 2500 series PLC racks, as well as legacy Simatic 505 (TI505) systems. It accepts universal AC input or DC backup and provides regulated 5V DC for logic and 24V DC for I/O modules. This module is a drop-in replacement for the Siemens 505-6850 or CTI 2500-PWR75.

Input Specifications

AC input: 85-264V AC (47-63 Hz), single-phase. DC input: 100-300V DC (backup capability). Inrush current limited to<30A peak. Efficiency: 85% typical at full load. Power factor correction (active PFC) meeting EN 61000-3-2. The supply includes a front-panel fuse (5x20mm, 4A slow-blow) and a power on/off switch. Input connection via screw terminals (L, N, PE).

Output Specifications

Main output: 5V DC ±2% at 10A (50W). Secondary output: 24V DC ±5% at 1.04A (25W). Combined total 75W maximum. Ripple and noise:<50 mV peak-to-peak on 5V, <100 mV on 24V. Hold-up time: 20 ms at full load. Overvoltage protection: 6.2V on 5V, 30V on 24V. Overcurrent protection: 110-140% of rated current (hiccup mode for 5V, current limiting for 24V). Short-circuit protected on both outputs.

PLC Rack Integration

The 2512 is compatible with CTI 2500 backplanes (series 2500, 2505, 2510, etc.) and Simatic 505 racks (e.g., 505-8000, 505-8005). It occupies the leftmost slot of the rack and provides power to the backplane for CPU and I/O modules via edge connectors. The module also supplies 5V standby to certain CPUs. A green LED indicates power good. The module does not require separate configuration.

Mechanical and Environmental

Dimensions: 105 mm (H) x 45 mm (W) x 240 mm (D). Weight: 1.0 kg. Mounting: Clips into rack with integral locking lever. Operating temperature: 0-60°C (derate 2.5%/°C above 50°C). Storage: -40-85°C. Humidity: 5-95% non-condensing. Cooling: convection (no fan). The module is designed for pollution degree 2 environments.

Protection and Safety

Over-temperature protection: automatic shutdown at 85°C internal, auto-recovery. Isolation: 3000V AC input to output, 1500V output to ground. The supply is short-circuit proof and can withstand continuous overload without damage. It is certified to UL 508, CSA C22.2, and EN 60950-1 (for IT equipment). CE and RoHS compliant.

Diagnostic LEDs

Front panel LEDs: AC OK (green), DC OK (green for 5V), and OVERLOAD (red). The overload LED flashes when overcurrent or overtemperature occurs. These signals are also available on an optional remote alarm connector.

Applications

Used in CTI 2500 and Simatic 505 based control systems for manufacturing, water treatment, and energy management. This power supply is often replaced when original units fail, as the 2512 provides improved efficiency and universal input over older supplies.

Compatibility Notes

Fully compatible with CTI 2500 CPUs (2500-C100, 2500-C200, 2500-C300) and all CTI I/O modules (2500 series). For Simatic 505 systems, it works with CPUs 505-5204, 505-5270, and 505-5725, as well as all 505 I/O modules. No adapter required.

Installation Guidelines

Ensure rack is powered off before insertion. Tighten the hold-down screw. Do not block ventilation slots. Connect ground terminal to panel ground. For AC backup application, connect DC input in parallel with AC (automatic switchover).

Conclusion

The CTI 2512 provides a reliable, high-efficiency 75W power source for CTI 2500 and Simatic 505 PLC systems. Its wide input range and robust protection make it an excellent replacement or upgrade for legacy power supplies.