PROFIBUS DP master for ET200S — 244 byte I/O, isolated RS485
The 6ES7151-7FA00-0AB0 is the PROFIBUS DP master interface module for the Siemens ET200S distributed I/O system. It handles 244 bytes of process input data and 244 bytes of process output data over an isolated RS485 physical layer, making it the communication gateway between the ET200S station and a higher-level DP master. The module supports programming in FBD, LAD, and STL, with SCL available as an optional add-on.
Integrated work memory and retentive data
The module carries 64 kbytes of integrated work memory, which the evidence notes accommodates approximately 10 K instructions. The backup time for retentive data is 6 weeks at 40 °C ambient, so a powered-down station holds its parameters through a typical plant outage without external battery support. Retentive data — inputs, outputs, memory bits, DBs, timers, and counters — must be restarted at each restart, which is normal for an ET200S slave interface that re-synchronises with the DP master on power-up.
Panel fit and DP master variant
The module body is 60 mm wide and 119.5 mm high, with the DP master sub-module occupying a 35 mm slot within that footprint. It snaps onto the DIN rail in the ET200S station, and the isolated RS485 interface means the DP line can run a different ground reference from the backplane without coupling noise into the I/O bus. SYNC/FREEZE is supported, so the module can synchronise output updates across multiple ET200S stations for coordinated motion or process steps. Routing is also supported, allowing the DP master to pass telegrams between subnets.