FM 450-1 counter module for S7-400
The Siemens 6ES7450-1AP01-0AE0 is an FM 450-1 counter module for the S7-400 rack. It provides two 32-bit (or ±31-bit) counter inputs with a maximum counting frequency of 200 kHz, making it suitable for high-speed position or pulse counting from incremental encoders. The module integrates 6 digital inputs and 4 digital outputs, plus a dedicated RS 422 encoder interface for differential signals. The encoder supply is 5.2 V ±2 % from the module's own 5 V rail, and the 24 V field supply is 1L+ (-3 V).
Counter inputs and encoder interface
Each counter input accepts differential RS 422 signals with a minimum differential voltage of 0.5 V. The module supports one pulse train with one direction level per channel, and the minimum pulse width is parameterizable: ≥2.5 µs at 200 kHz or ≥25 µs at 20 kHz. The 24 V digital inputs have a signal "1" threshold of +11 to +28.8 V, and the 24 V digital outputs are rated 0.5 A per channel with clocked electronic short-circuit protection. The module also provides a 220 Ω terminating resistor for the RS 422 line. Diagnostics include a parameterizable diagnostic alarm, a hardware interrupt, and status indicators: 14 green LEDs for CR, DIR, inputs, and outputs, plus red LEDs for external fault (EXTF) and internal fault (INTF).