Plant engineering for round timber: SPS testing on a simulation model reduces commissioning time by three days
HOLTEC develops and supplies bespoke systems for round timber handling and is headquartered in Hellenthal. The company has been working with SimPlan since 2019.
Initial situation: New control system, limited time on site
At a new round timber yard built by HOLTEC, a PLC handles the control functions. One section of the system placed particular demands on the PLC programme, as this is where the system diverts round timber into a bypass and subsequently feeds it back into the material flow. Errors in this logic usually only become apparent during on-site commissioning. However, any corrections made there cost time, as the actual system is shut down whilst the team adjusts the programme.
Objective: To validate the PLC programme prior to commissioning
HOLTEC therefore wanted to test and validate the PLC programme before commissioning on site. The focus was on two tasks:
- testing and validating the PLC for the selected section of the round timber yard
- checking the processes involved in diverting timber to the bypass and reintroducing it into the flow
Solution: Simulation model and emulated PLC working together
SimPlan modelled the section of the round timber yard as a simulation model in Plant Simulation 16.0. The control system did not run on real hardware, but as an emulation in PLCSIM Advanced 3.0. The PLC programme was sourced from TIA Portal Step 7 V16. The model also offered the following functions:
- The PLC controls the entire material flow in the model, just as it will later in the real plant.
- The model logs selected PLC errors so that the team can analyse them in detail.
Software used:
- Plant Simulation
- PLCSIM Advanced
- TIA Portal Step 7
Results: Validated control system and commissioning completed three days earlier
As the PLC had to operate within the virtual model, weaknesses were identified well in advance of the on-site commissioning date. The virtual commissioning delivered tangible results for HOLTEC:
- Several errors in the PLC were identified in advance and could be rectified before commissioning began.
- Parameterisation was carried out virtually on the model.
- The part of the PLC under investigation was fully validated, which is why on-site commissioning was completed three days faster.
Errors are found in the office rather than on site
The HOLTEC case study demonstrates just how much time a PLC test on a simulation model can save. This is because any fault detected whilst still in the office no longer causes downtime on site. It is not necessary to model the entire system virtually: even a critical sub-system, such as a bypass with re-injection, is sufficient to significantly shorten the commissioning process. For plant manufacturers in production and logistics, this means less risk when it comes to meeting deadlines on site, as the control system arrives at the construction site having already been tested.
