Two ASCOM mounts on one computer?

[james_screech]

Does anyone know if its possible (and if so how) to control two mounts using the the same ASCOM driver (Celestron) from a single computer at the same time?

I'm look at setting up a second mount for DSLR photometry while using my main mount/telescope with my CCD.

James

[Dr_Ju_ju]

If you have multiple Ascom configurations using different com ports\drivers etc. and as long as Windows recognises each device\application as separate entities, then yes it can be done...

[james_screech]

5 minutes ago, Dr_Ju_ju said:

If you have multiple Ascom configurations using different com ports\drivers etc. and as long as Windows recognises each device\application as separate entities, then yes it can be done...

How do I create multiple Ascom configurations? Do I need to install Ascom several times in different folders?

James

[Dr_Ju_ju]

Hi James,

When you've plugged in both mounts to your PC, in "device manager \ ports" you'll hopefully see an entry for both. Then, as long as you have either 2 installations of the mount driver or as I use EQMod\EQDirect (http://eq-mod.sourceforge.net/introindex.html), which is able to configure 2 separate instances of the  mount control. Then in 2 instances of CTC, I assign one driver instance to one & the other to the 2nd running copy of CTC.

 

[james_screech]

40 minutes ago, Dr_Ju_ju said:

Hi James,

When you've plugged in both mounts to your PC, in "device manager \ ports" you'll hopefully see an entry for both. Then, as long as you have either 2 installations of the mount driver or as I use EQMod\EQDirect (http://eq-mod.sourceforge.net/introindex.html), which is able to configure 2 separate instances of the  mount control. Then in 2 instances of CTC, I assign one driver instance to one & the other to the 2nd running copy of CTC.

 

But its not possible to install two instances of the Celestron driver, when installing the second one it un-installs the first, so I still get just one.

 

James

[Dr_Ju_ju]

I don't have a Celestron mount, but others may be able to say if an EQDirect USB\Serial cable is able to be used with them ??  if so then, you can either buy or make a couple & use the EQMod drivers & leave out the Celestron drivers.

[brantuk]

You don't install "instances" - you install the software which is usually reenterant code and only requires installing once. Then the operating system will create two running processes (or "instances") as and when you invoke them.

All you need to do is configure which ports and devices each instance is to use - the operating system will take care of all the memory allocation and addressing for each instance and run them both at the same time - so you don't need to worry about it.

[chrisshillito]

On 04/03/2016 at 16:46, brantuk said:

You don't install "instances"

Really??  If you're using ASCOM then each driver when it installs registers itself with ASCOM using a unique ID - each driver can support only one piece of equipment  and this presents a problem for folks with multiple mounts or focusers of the same type. One easy way to get round this is for manufacturers/developers to provide multiple instances of the drivers each being assigned a unique  ID. This is what we chose to do with  EQMOD where the installer gives you the option  install a second instance of the driver. So yes, you may find yourself installing instances!

Chris

[brantuk]

Might just be terminology confusion here - an "instance" in computing terms is a running process managed by the OS. You can have many identical processes but they all come from the same reenterant code which only needs installing once (no point having several files with identical code cluttering up the disk).

What EQMOD installer calls it I don't know - probably a registration or licensing issue using unique id no's on the drivers as you say. But last time I read the ASCOM docs it said ASCOM was all reenterant code and you can fire off multiple processes (or instances) of it to drive more than one mount from the same platform.

[chrisshillito]

Fortunately I do a bit about the know the EQMOD installer, and it allows you to installs two separate instances of the EQMOD driver exe (three if you include the simulator). Instance is simply a term that indicates "one of many" and is widely, and correctly applied to many aspects of computing - it isn't restricted to processes running under an OS.

The real issue is that ASCOM drivers  have settings associated with them that are effectively accessed via the drivers ProgramId. If you run up multiple instances of the same driver exe then each instance will run with identical settings, and this includes things like serial port COM number etc. Clearly that isn't going to work well in practice even if the re-entrant nature of the code allows it.  The workaround (as recommended by ASCOM ) is to produce two (or more)  identical drivers that differ only by their Program ID - doing this will mean multiple copies of the driver will appear in the ASCOM chooser and each will have its own settings. Of course that doesn't mean that some ASCOM driver developers haven't come up with more sophisticated/creative workarounds.

Chris.

[brantuk]

That's useful to know Chris - thanks for clarifying how EQMOD is implemented under ASCOM - I'll watch for that if ever I run more than one mount.

[perfrej]

If the driver is in-process, then you can create any number of instances to different com ports. If the driver is out-of-process (also called "local server") then all instances will share the same com infrastructure, so you need a separate driver with a different ID in order to make it work.

EQMOD is local server. Don't know about the Celestron one...

 

Just sayin'...

 

/per