Wireless safety control
But how can a battery-powered shuttle be controlled in a safety-oriented manner and linked to other plant components, especially with regard to emergency stop interlinking? In the end, the Safety Simplifier was chosen because the company was looking for a compact and wireless safety controller that could communicate safe signals wirelessly to an input and output station. The Safety Simplifier decentralized safety PLC with 14 safe, digital inputs and outputs each and optionally 2 relay outputs seemed ideal for this task.
A total of 4x Safety Simplifiers were used for the project: On the line mover, on a door, and at the loading and unloading stations, i.e. at the end of the line. The Safety Simplifiers were each individually equipped with integrated operating elements, via which safe functions such as the emergency stop or the reset were mapped.
The Safety Simplifier now sends the signals wirelessly on a frequency of 2.4 GHz to the other participants in the system. The special feature here is that this is not a simple transmitter and receiver model, but through mutual multi-master communication, a comprehensive network of safety communication is established, in which each Safety Simplifier also serves as a repeater. This means that even longer distances can be bridged reliably and quickly without the use of cables! If several Line-Mover systems should operate side by side in the future, 15 channels are still available on the 2.4 GHz frequency so that they do not interfere with each other. In total, up to 16 Safety Simplifiers (256 I/Os) can communicate with each other in one system.