Partial retrofit of an automation/logistics system for an order picking warehouse

Task

The order picking warehouse dated from the 1990s and used controller technology based on the Simatic S5. The controller components had long been discontinued, which made it increasingly difficult to source spare parts. There was a growing risk that lengthy, incalculable downtimes would result if a component failed. Lasting, reliable operation was no longer assured. HEITEC was tasked to analyze the situation and the risk of an outage, and to perform a retrofit.

Implementation

A requirements analysis was performed to determine the general quality of the warehouse, the condition of its electrical and drive systems and the controller and distributed control systems, and also to examine repair reports to establish the availability of spare parts and servicing requirements. Based on the analysis, the decision was taken to retrofit the controllers in the materials handling area, since that was where most of the malfunctions were occurring with increasing frequency. In particular, there were problems with the positioning of the traversing car, which would have brought the whole warehouse to a standstill if it failed. The warehouse used Simatic S5 controllers for materials handling, order management, and system visualization. HEITEC replaced both these S5 controllers with a Simatic S7-1500, which combined the functions of the two older controllers. On the traversing car, the position measuring system was replaced with a state-of-the-art, optical laser measuring system that is much less sensitive to damage and wear, and the drive converter was replaced with another that included a positioning function. Switching to the Simatic S7 means that many functions like controlling the proportional valves for the hydraulics are now performed directly within the controller. Because the S5 controllers in the shelf servicing units were still working satisfactorily, they did not have to be replaced, and a series connection to the new controllers was provided. This partial retrofit shows that retrofits do not have to involve replacing all the controller technology, resulting in a much more cost-effective solution.   

Customer benefit

• Low-cost solution thanks to a partial retrofit
• Increased warehouse availability
• Reduced risk of outage and fewer malfunctions

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