DP and FMS telegram structure

Information is transmitted on Profibus-DP and Profibus-FMS networks in byte sequences called telegrams, consisting of a series of bytes controlled by an even parity bit and transmitted asynchronously, framed by a start (logic level 0) and stop (logic level 1) bit.

Each telegram byte is transmitted on 11 bits. The telegram format is based on the IEC 60870-5-1 standard, taking into account the choice of start and end characters, synchronization without pause between characters, parity bit and control key. The case of Profibus-PA telegrams 7.3