Changeover to PCS7 control unit for a dried sewage sludge silo


The first of two dried sewage sludge silos, that charge an incinerator in collaboration, was extensively modernized. The silo was out of order for approximately one year to realize the considerable conversion measures. During the modernization not only parts of the hardware were renewed but also the existing S7 control unit including InTouch®-visualization was switched to a Simatic-PCS7-control system.

Now it was our task to integrate the silo into the processes. The tight schedule was our biggest challenge: We only had four hours of downtime at our disposal as the incinerator was integrated into the running production process. We integrated the available control units into an existing PCS7-environment and embedded the new hardware components. Afterwards we put the old control unit out of operation and changed the control units of the old system step by step to the new PCS7-control system.

Moreover we integrated a MultiFlex-weighing system into the machine. This means a screw weigh feeder for the continuous dosage according to weight units. Besides we brought the whole system up to date of the latest guidelines according to the requirements for explosion-proof zones to receive the necessary certification of the Technical Inspection Agency.

To realize such complex works in limited time an optimal planning is of the utmost importance. Therefore we had constructed the whole system in EPLAN P8 and inserted a new customized designation code.


Construction, stone and soil


With the new control unit the combustion process runs more constantly in collaboration with the second silo than before. Therefore it is possible to burn more dried sewage sludge thanks to an improved redundancy. The new system also prevents down times during maintenance work.

Moreover the system was updated with the latest safety technology according to the latest guidelines.

It makes us a little proud that we kept the tight schedule for the conversion of the system: The topical realization of the works went completely according to plan.

Besides it was the first project with a PCS7 control unit. Therefore we now have another system for our customers in our competence portfolio.


  • Simatic PCS7
  • Simatic ET 200SP
  • ABB frequency converter, model ACS355, ACS880
  • MultiFlex-screw weigh feeder
  • Profinet / Profibus