Cannot change PrimaLuce Rotation Reversal When Connected to ACP

[William Bristow]

Hi Bob.

I wanted to raise this query with you once I had the guiding problems sorted with my PrimaLuceLab ARCO rotator.

I have added four screen grabs because I doubt you'll have the PrimaLuceLab software and drivers on any of your test machines.

The issue here is that PrimaLuceLab (PLL) have their own application called "PLAY" where you calibrate all their hardware and can also run acquisitions and point a telescope etc.

For PLL's range of ARCO rotators the rotation calibration and a master control of direction of rotation is configured here:



Play Rotator Settings.jpg


This master control for direction of rotation applies to using "PLAY" itself as well as any external application connecting to the ARCO rotator, such as ACP via ASCOM.

There is a problem though because with a standard refractor the direction of rotation for a correctly installed and mechanically coupled ARCO the direction of rotation is correct in "PLAY" when the setting for "Reverse Rotator direction” is disabled, but to get ACP to rotate the rotator in the correct direction I have to select the option "Reverse Rotator Direction" in "PLAY" and that means that PLAY itself, and any other applications seeking to connect to the ARCO rotator can no longer control the direction of rotation correctly.

PLL however thought about this and made it possible to change the rotation direction in their ASCOM driver so that any ASCOM application can control the direction of rotation independently from the master switch in "PLAY"

But, there is a problem that only seems to affect ACP, the PLL ASCOM driver won't let you change the rotation direction unless you are "Connected" to the ARCO first:

ACP Properties.jpg



But, in ACP once you are connected to the rotator you can't select the setup button to access the ASCOM properties, the Setup button is "Greyed out":



ACP Rot Setup.jpg


And, here's the strange part, using the same PLL ASCOM driver in MaxIm's Observatory Control you can "Connect" to the rotator and then access the ASCOM properties to configure the rotation direction:

MaxIm ASCOM setup.jpg

So the question is how do I configure the PLL ASCOM driver Reverse Rotator option specifically for ACP when I can't reach the ASCOM driver once the rotator is "Connected" in ACP?


Bob, there's no great urgency to solve this for me because I have changed the "Reverse Rotator direction" master switch in the PLL "PLAY" software and as I'm only using ACP I can work around the incorrect direction of rotation when calibrating the rotator in PLAY, its just another idiosyncrasy of the software-hardware environment but I wonder if this is an oversight in ACP or a bad software design of the PLL ASCOM driver...or something else...?

William.

[Bob Denny]

I doubt you'll have the PrimaLuceLab software and drivers on any of your test machines.

Definitely not. I don't keep any hardware here since I only speak ASCOM and the simulators always act correctly :-)

Rotation direction

For reference, no matter what, Position Angle is always counter clockwise (looking at the sky from behind the optics). There is no end to the confusing diagrams, with south up etc. But simply stated it is the angle from North to the object, measured counter clockwise from North. So one should never play with the rotator's reversal switch if using for astronomy.

This isn't the first rotator I have encountered that has the wrong direction as shipped. The old Optec rotators were originally shipped with the wrong direction for astronomy and had to have the Reverse option set. More recently they ship them with the correct CCW direction as the default. I know how to recognize a reversed rotator if I can see an ACP run log. You should be able to see this as well with the "PA error..." messages logged, repeated attempts to correct the PA from mechanical to sky, followed by another PA error, with the rotator essentially "chasing its tail".

Your Question

how do I configure the PLL ASCOM driver Reverse Rotator option specifically for ACP when I can't reach the ASCOM driver once the rotator is "Connected" in ACP?

ACP is designed to prohibit changes to device settings when it is connected to a device since it is an automation system. ACP would need to re-read the ASCOM properties as needed, check them again, and then possibly adjust its operation to accommodate a change, while it is using the device. Impractical. It is assumed that the device is installed and checked out before connecting to ACP for automated use. So preventing you from adjusting settings when in use by ACP is by design.

Do you have to calibrate this rotator every time it's powered up? Aren't calibration and reversal settings "one time" until it's physically disassembled, etc? In any case if it requires calibration with it in the mode where it rotates clockwise for increasing angle, then one could argue that it was not designed for astronomical use :-) ACP is certainly not wrong to expect its mechanical angle to increase counterclockwise.

Bob, there's no great urgency to solve this for me because I have changed the "Reverse Rotator direction" master switch in the PLL "PLAY" software and as I'm only using ACP I can work around the incorrect direction of rotation when calibrating the rotator in PLAY, its just another idiosyncrasy of the software-hardware environment but I wonder if this is an oversight in ACP or a bad software design of the PLL ASCOM driver...or something else...?

It appears that calibration is the only time you would need to flip the reversal switch, so calibrate it, don't forget to set it for CCW rotation thereafter and then use it for astronomy with any software, until it is mechanically moved etc..