Robust Repeating Mode - Procentec ProfiHub B2FOR+ User Manual

In robust repeating mode, only messages starting with a valid PROFIBUS start delimiter are repeated (SD1, SD2,
SD3, SD4 and Short Acknowledge). In Normal mode, every bit is transferred immediately onto the other
channels.

2.13 Robust Repeating Mode

The B2FOR+ / B4FOR+ has two repeating modes: normal (rotary switch setting 0 and 3) and Robust Repeating
(rotary switch setting 1, 2, 4 or 5). In normal mode the bits are transferred directly on the other channel with a
minimal delay (see delay times in the Technical Data chapter). In Robust mode, the first byte is checked to
verify if the following bits are a real PROFIBUS message. If the byte is corrupt, the message will not be
transferred to the other channel. This helps network stability in EMC sensitive environments.
ATTENTION:
Using the ProfiHub B2FOR+ / B4FOR+ in Robust Repeating mode causes a delay in processing the telegrams. It
is required to increase the default MinTSDR in the PLC busparameters slightly. Recommended is to increase the
MinTSDR with a value according to the Delay Time table, column 'Robust Mode', described in the Technical
Data chapter. Generally a MinTSDR of 25 is sufficient.
ProfiHub B2FOR+ / B4FOR+ User Manual | August 2019 | © PROCENTEC 23/60