How many PROFIBUS DP repeaters can be installed in series?
There are lots of stories out there concerning this subject. The actual answer lies in the electronic components of the repeater. These determine the actual “maximum number. The digitalization from and to the opto-couplers in the repeater will make bits smaller or wider. If you put too many repeaters in series, the bits differentiate too much and messages are not recognized anymore. There are also repeaters available with no limit in serial placement. Check the manual of the repeater! It should state the maximum amount. For example: the Siemens repeater is 9, the ProfiHub is unlimited. Click here for a YouTube video The second step is changing the busparameters. All repeaters have a delay time. If you put a large quantity of repeaters in series you might have to change the Tslot busparameter to a higher value.
