E Series

1972 - 1978

Oertling ETP40

These were a mechanical top pan hybrid fitted with a Moire fringe sensors to determine the exact inclination of the beam. They had a digital display using TTL electronics

Four versions were made:

Model No. Made Years
ETP40 4 1972 - 1975
ETP41 1 1975
E22TD 5 1975 - 1977
E32TD 35 11974 - 1978