APPM and 360 degree slew

Eric Claeys

Two nights ago I tried running APPM.  It started off going to zenith and solved the 1st point ok.
When going to 2nd point (DEC = -20, HA = -2.8378) it slewed 360 in RA (the OTA went below the mount all the way around - luckily it didn't hit anything). APPM had a Status of "Slewing" until it timed out five minutes later with an error ("Slew did not reach destination") and it retried the slew.  I got out of APPM and quit for the night.

Last night I tried running the same APPM but in test mode (i.e., no plate solves since it was light outside and I just wanted to test).
I used SGP for the camera connection and the only thing SGP was connected to was the camera.
Other than APPM, nothing was connected to the mount.
Meridian limits were ON in APCC and Horizon limits were OFF.
This time it got through point 45, then for point 46 (DEC = 0, HA = -4.000) it first slewed the OTA to the east side pointing more or less at the meridian with counterweights pointing straight west.  It paused a few seconds, then moved slightly, then paused again slightly, then started slewing in RA to the west side and kept going for a 360.
APPM had a Status of "Slewing" for five minutes, then timed out and started ANOTHER 360 slew.
I pressed the Emergency Stop.

I got out of APPM and tried two more tests but started at point 45.  In both cases, going to point 46 did a 360.

I uploaded the APCC and ASCOM zipper files of the full run (45 good points, then the 360) as well as a screenshot from that run and a screenshot showing the OTA going under the mount from the 3rd run.  It's in the Files/EricC folder and is called

I have:
  * APCC Pro
  * ASCOM driver 5.10.02
  * a GTOCP4 box with firmware VCP4-P01-01
  * 1100 GTO with encoders
  * A new laptop running Windows 10

Any ideas how to fix this?


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