What it is and why it matters
The Siemens 6ES7350-1AH03-0AE0 is a single-channel counter module for the S7-300 family, accepting incremental encoders (both symmetrical RS422 and asymmetrical) and delivering 32-bit or ±31-bit count values. It handles counting frequencies up to 200 kHz, with three dedicated digital inputs for gate start, gate stop, and setting the counter — plus two digital outputs for onboard threshold response.
The module occupies a single-wide slot (40 mm) and requires a 20-pin front connector, which is a standard S7-300 accessory. Isolation between the channels and the backplane is optocoupled, tested at 500 V. Power loss typically runs 4.5 W.