Siemens 6ES7 277-0AA22-0XA0 Profibus-DP Slave Module

Siemens EM 277 PROFIBUS-DP Slave Module, model 6ES7 277-0AA22-0XA0, is an expansion card for SIMATIC S7-200 PLCs that lets the CPU operate as a PROFIBUS-DP slave on a DP network. It provides one RS-485 port that supports both PROFIBUS-DP slave and MPI slave protocols, enabling data exchange between S7-200 devices and a DP master. The module supports a wide range of baud rates: PROFIBUS-DP speeds from 9.6 to 500 kbit/s and MPI speeds of 1, 1.5, 3, 6 and 12 Mbit/s, with automatic negotiation in compatible configurations. Station addresses range from 0 to 99 and are set with rotary switches; MPI connections total six, with two reserved (one for the programming device and one for the operator panel). The network can accommodate up to 126 devices in total and up to 32 devices per DP segment, making the EM 277 suitable for integrating S7-200 with higher-level controllers or SCADA systems via a DP master. Intended for industrial automation, this DP slave module supports seamless read/write access to I/O and parameter data between the S7-200 and DP masters, enabling reliable, fieldbus-based communication in machines and processes.