For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ighvh:branches:science:EtherLab14/openSUSE_Tumbleweed/home:ighvh:branches:science:EtherLab14.repo
zypper refresh
zypper install ethercat
For openSUSE Factory run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ighvh:branches:science:EtherLab14/openSUSE_Factory/home:ighvh:branches:science:EtherLab14.repo
zypper refresh
zypper install ethercat
For 15.5 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ighvh:branches:science:EtherLab14/15.5/home:ighvh:branches:science:EtherLab14.repo
zypper refresh
zypper install ethercat
For 15.4 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:ighvh:branches:science:EtherLab14/15.4/home:ighvh:branches:science:EtherLab14.repo
zypper refresh
zypper install ethercat