Commissioning Experience with Undulators at PETRA III

Meanwhile all remaining free straight sections in the reconstructed octant of the PETRA III light source have been filled with undulators. In order to make full benefit of the small beam emittance, close limits apply to magnetic field errors of the insertion devices. By individual tuning of all poles, a phase error smaller than two degrees could be achieved regularly. This work summarizes tuning procedures and magnetic measurement results, compares to optical measurements, describes commissioning issues, and reports on experience with background radiation after the first three years of operation.