Siemens Simatic 505 16-Slot PLC Rack (T1545) for I/O Chassis

The Siemens Simatic 505 16-slot rack (model designation T1545) is a backplane chassis for the SIMATIC 505 PLC family. It serves as the foundation for building a control system, housing the CPU, power supply, and up to 16 I/O modules. This rack is fully compatible with legacy TI505 series modules from Texas Instruments and Siemens.

Physical Specifications

Number of slots: 16 positions for any 505 family module (CPU, power supply, I/O, specialty). Dimensions: 482 mm width (19 inch rack mountable), 265 mm depth, 177 mm height (4U). Material: galvanized steel with replaceable backplane. Weight: approximately 3.5 kg. Rack can be panel mounted or placed in a standard 19-inch cabinet using optional ears.

Backplane Communication

Parallel backplane bus with separate data, address, and control lines. Supported bus protocols: 16-bit parallel I/O access. Maximum backplane transfer rate: 1 MB/s. The rack includes a dedicated slot for the CPU (slot 1) and a slot for the power supply (slot 2). Remaining slots are numbered 3 to 18 for I/O modules. Daisy-chain capability for multi-rack systems using expansion cables (up to 3 racks total).

Power Distribution

The backplane distributes +5V DC (10A max) and +24V DC (2A max) from an external power supply (e.g., 505-6850, 505-6880). Each slot has gold-plated edge connectors rated for 500 insertion cycles. The rack also provides I/O bus termination jumpers for noise reduction on long backplanes.

Compatible Modules

Any SIMATIC 505 or TI505 module that fits the standard form factor. Examples: CPU 505-5204, 505-5270; digital I/O 505-4256, 505-4288; analog I/O 505-4485, 505-4508; specialty modules like 505-5010 (thermocouple) and 505-5712 (motion control). The rack also supports remote I/O adapters (505-6108A).

Environmental Ratings

Operating temperature: 0°C to 60°C. Storage: -40°C to 85°C. Relative humidity: 5-95% non-condensing. Vibration: 2g at 5-500Hz. Shock: 30g. Pollution degree 2. The rack is UL 508 listed and CE marked.

Installation and Grounding

Mounting holes: four M6 holes on 9.5mm centers. Use a grounding strap from the rack’s grounding stud to panel ground. Separate I/O ground from logic ground as per manual. Spare slots should be covered with blank covers (505-4911) to maintain airflow and EMC integrity.

Included Components (T1545 assembly)

The T1545 usually includes the rack frame, backplane PCB, and terminal numbering strip. Field wiring terminations are done on each module individually; no screw terminals on rack. Din rail for cable management is optional. Replacement parts include slot covers and backplane replacement kit (505-8720).

Applications

Used in legacy industrial control systems for automotive, chemical, and material handling. Many plants still run Simatic 505 systems; the 16-slot rack allows large I/O counts per chassis, reducing footprint. It is also used in training simulators and retrofit projects where keeping 505 I/O is required.

Maintenance

Periodic inspection of edge connector for corrosion or dust. No moving parts. Replace if backplane traces are damaged. When inserting modules, ensure rack power is off to avoid latch-up.

Conclusion

The Siemens Simatic 505 16-slot rack (T1545) is a durable and spacious backplane for building or expanding SIMATIC 505 control systems. Its standard 19-inch form factor simplifies cabinet integration.