Here is a list of all the current encoder systems on the telescope, with links to documentation. Feel free to update as needed.

Enclosure Azimuth

Original PCV / WCS Encoders: Pepperl+Fuchs PCV80-F200-R4-V15-LS221

Two encoders, spaced at ~90 deg apart on the lower Service Ring level.

Manual:

Issues with the current encoder - track not perfectly circular, enclosure shifts with thermal expansion and wind, and limited depth of field mean that they often fault out despite our attempts at adjusting the position. Additionally, they communicate via WCS RS-485 to Ethernet/IP modules which tend to fault and need their power cycled occasionally.

Troubleshooting - if we get consistent out of range errors, it’s possible to adjust them such that they work better at one side of the observatory. Also persistent comm errors can be fixed by power cycling the WCS module in Cabinet 201; this will show up as an error on the RSLogix device tree as well.

New PXV Encoders - PXV100A-F200-B28-V1

These encoders have a much larger depth of field, (>100 mm vs ~30 mm on the old encoders), 0.1 mm resolution,, are more reliable, have ethernet output (note, Profinet, not Ethernet/IP, thus the gateway requirement), and so far are working much better. They are mounted one level above the existing encoders on the upper Service Ring level. The tape counts up as AZ increases, opposite to the old PCV/WCS encoders, and 0 m on the tape is roughly due north. Also of note on the new encoders, the tape is mounted on the fixed foundation, and the encoders move with the Enclosure, opposite to the old encoders.

Manual: