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Thread: Two GEM Scripts

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  1. #1
    Join Date
    Oct 2005
    Strongsville, OH

    Default Two GEM Scripts

    As part of my testing process, I've developed two scripts that I decided to publish since they might be helpful to others trying to diagnose problems around GEM flipping. They are not particularly elegant as I stole most of the code from other ACP scripts and cobbled them together. They assume your mount is a GEM that needs to flip. If that's not the case, these scripts aren't for you.

    GemFlipper.vbs - The core purpose of this script is to exercise the mount driver and ACP's mount driver polling process around the flip point, assumed to be the meridian. Specifically, it is testing whether the SideOfPier status is updated properly after the flip has completed. Generally, you will want to turn on your driver's logging facility and compare it to ACP's log to troubleshoot.

    The script:

    1) Requests number of seconds to complete a flipping slew (not using simulated mount).
    2) Slews close to the meridian (ACP's convention - target is in the East).
    3) Slews 30 seconds East of the meridian (ACP's convention - target is in the East).
    4) Waits 45 seconds.
    5) Issues slew command - which should initiate a flip.
    6) Tests SideOfPier status.
    7) If ok, repeats starting at #3 for up to 10 times (3 times if using simulated mount).
    8) If not ok, wait one second and test again.
    9) If still not ok, terminate run (disconnecting mount, closes logfiles).

    This script does not respect ACP's flip settings or FlipConfig.txt. If your mount's flip point is not the meridian, the script will need to be modified to suit your needs. The script can be run using simulators. I strongly suggest doing this to see how it works before using your real mount.

    GEMFlipPointTest.vbs - There's no automated process (that I know of) that allows you to determine exactly where your mount flips. Part of the issue is there are potentially three sources for LST (when the meridian is crossed at a given RA): 1) ACP, 2) mount driver, and 3) mount firmware. The ACP console displays what the mount driver reports as LST, however, we don't know for sure whether the driver is calculating this value or whether the driver is getting it from the mount. Since each of these systems contains latitude/longitude and time data and since they might not all be the same in each system, this creates uncertainty. For sure, it's the data in the mount and its firmware calculation that actually determines when the flip will occur. This script will determine where the flip point is. It is assumed that the flip point is at the meridian and the log will reflect this. However it will still be able to determine the actual flip point even if it isn't at the meridian.

    The script:

    1) Slews close to the meridian (ACP's convention - target is in the East).
    2) Slews to a user-defined number of seconds East of the meridian (ACP's convention - target is in the East).
    3) Issues a slew command to this specified RA every 3 seconds (plus slewing overhead). Eventually, this will cause a flipping slew.
    4) The actual flip point (time relative to the meridian) is displayed and documented.

    The mount's starting RA for the test is a user-input value and represents the number of seconds the mount's position is East of the meridian. Assuming your mount flips at the meridian, a value like 30 seconds is reasonable (automatically entered if using the simulated mount). However, if the flip point is somewhere else, you can enter other values. Specifically, if the flip point is somewhere West of the meridian, a negative number can be entered for the starting point.

    The log shows, among other things, the time of the slew that flipped the mount relative to the meridian. The accuracy of the calculation is to within 3 seconds plus whatever time it takes to do a very small slew. For instance, using simulators, the accuracy of the flip time is 3 seconds (the delay time between slews) plus the slew time (2 seconds), for a total accuracy to within 5 seconds. The script can be run using simulators. I strongly suggest doing this to see how it works before running it with your real mount.

    I make no guarantees that these will meet your needs and I can't assume any responsibility or liability if things go wrong. Having said that, I use them and believe there should be no problems. You'll need to change the extensions from .txt to .vbs. I hope you find these useful.

    [edit 3/9/12] - I updated GEMFlipPointTest.txt to provide a warning if ACP's flip point settings are not 0. The script won't run unless they are both set to 0.


    Jim McMillan
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    Last edited by Jim McMillan; Mar 9, 2012 at 13:37. Reason: Update GemFlipPointTest.txt script



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