Retrofit of a bottle packaging line for DW Reusables

The line that packs bottles into crates at DW Reusables in Hum na Sutli consists of four segments. Three of them had no PLC control whatsoever - they ran purely on switches - and ENSO replaced the only existing PLC, an outdated Siemens S7-300, with a new S7-1200 controller.

Client

DW Reusables

Location

Hum na Sutli, Croatia

Industry

Reusable packaging

Platform

Siemens S7-1200

01 - Project context

Reviving the line for packing bottles into crates for DW Reusables

DW Reusables in Hum na Sutli runs a line for packing bottles into crates made up of four segments: a crate depalletiser, a bottle depalletiser, a packer that places the bottles into empty crates, and a palletiser for full crates at the end of the line.

Of the entire line, only the bottle depalletiser - a Transpak machine from Slovenia - had any PLC control at all: an outdated Siemens S7-300 with an HMI panel that no longer worked. The other three segments had no PLC whatsoever - all actuators were switched directly via switches and contactors, with no automated logic.

02 - Technical scope

A new PLC on all four segments, based on the existing electrical documentation

The line works in four steps: the first segment depalletises the bottle crates, the second depalletises the bottles themselves, which are then transported together with the crates to the third segment - the packer that places the bottles into the empty crates. At the end of the line, the palletiser stacks the full crates onto pallets.

Complete electrical documentation existed for the three segments without a PLC - the German equipment manufacturer had documented everything in detail - so we relied on it to create the new EPLAN project and write the PLC programs from scratch.

On the bottle depalletiser we replaced the old Siemens S7-300 with a new S7-1200 controller and renewed the wiring.

Alongside the PLC and EPLAN work, the pneumatics were also renewed - some of the cylinders and valves were kept, worn ones were replaced, and new air preparation units with pressure switches were installed on all four segments. The existing SEW brake motors and frequency inverters (Danfoss, Lenze, Delta) were integrated into the new PLC via conventional electrical signals.

Retrofit of the only existing PLC (S7-300 → S7-1200)

The bottle depalletiser - a Transpak machine from Slovenia - was the only segment of the line with any PLC control: an outdated Siemens S7-300 with an HMI panel that no longer worked. It was replaced with a new Siemens S7-1200 controller.

Three segments without a PLC, redesigned from scratch

The crate depalletiser, the packer and the full-crate palletiser had run purely on switches until then - actuators were switched directly by contactors, with no PLC logic. Based on the existing electrical documentation, we created a new EPLAN project and wrote new PLC programs for all three.

Targeted renewal of cylinders and valves

Some of the pneumatic cylinders and directional valves were in good condition and were kept, while worn components were replaced - a renewal, not a blanket replacement of the entire pneumatics.

New air preparation units with pressure switches

New air preparation units (filter, regulator, lubricator) with a pressure switch for monitoring the working pressure were installed on all four segments.

Integration of the existing drives

The conveyors were driven by SEW brake motors, and the frequency inverters were a mix of Danfoss, Lenze and Delta units - all connected to the new PLC via conventional electrical signals.

Networked segments and remote access

All PLCs are connected to a shared LAN, so the segments exchange signals with each other, and ENSO has remote access to intervene and resolve PLC issues at any time.

03 - Scope of work