TM Count 2x24V – Encoder Interface for ET 200SP
The Siemens 6ES7138-6BA01-0BA0 is a Technology Module for the ET 200SP distributed I/O system, handling one or two incremental or absolute encoders via RS-422 or TTL 5 V push-pull signal levels. It also accepts 24 V inputs (L+ with -0.8 V drop), so it covers both legacy 5 V encoders and modern 24 V units without an external converter. The module sits on the ET 200SP BusAdapter and communicates over PROFINET or PROFIBUS with 16 bytes of input data in standard mode, dropping to 4 bytes when Fast mode is enabled for tighter cycle times. Diagnostics are built in: group error alarms, wire-break detection on the encoder lines (thresholds between 48 Ω and 12 kΩ), and short-circuit monitoring. The module supports isochronous mode, which synchronizes the counter value with the PROFINET cycle for deterministic motion control applications. Monoflop time is adjustable: 16, 32, 48, 64 µs or automatic. Shielded cable max length is 1 000 m.