Directing Traffic Along a Production Line
A heavy equipment manufacturer used Automated Guide Vehicles (AGVs) to transport their products along an assembly line. The AGVs followed a magnetic path along the floor, which worked well. The plant’s wired serial communications were also quite reliable. There was, however, no direct link between the mobile AGVs and the central PLC that directed the manufacturing processes at the various stations along the line. As the AGVs operated independently of one another, there were occasional collisions, which would shut down the line. The manufacturer needed a wireless solution that would give the PLC the ability to control all of the AGVs and ensure that they didn’t interfere with one another.
The manufacturer equipped each of the AGVs with B+B’s Zlinx® ZZ24D-NB-LR – 2.4 GHz, short range wireless I/O modules. The Zlinx modules are bidirectional, so they are not only able to report the location of the AGVs as they move along the production line; they give the PLC the ability to issue start and stop commands. The assembly line didn’t have to be re-engineered, and the manufacturer didn’t have to make a large capital investment, but the collision problem was eliminated.