USB over Ethernet

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  • #579285
    Grant Privett
    Participant

    Separate networks sounds a good idea. Sneaky 🙂

    #579286
    William Bristow
    Participant

    Hi Nick.

    If you want an independent low power 12v rain monitor with switched output for the dome controller take a look at the Hydreon RG-11. I have one as a belt-and-braces backup for the AAG. The RG-11‘s switched output is wired in parallel to the AAG so either unit will cause Pulsar’s Rigel controller to close the shutter.

    The RG-11 uses IR to detect rain droplets on a transparent dome, same as automatic windscreen wiper control in cars. It does have an internal heater to help evaporate condensation and works in a different way to a capacitive or resistive water sensor by reacting to sudden changes in reflected IR on the clear dome to trigger the relay so even if static water droplets are on the dome as long as no further droplets are seen then it will open the relay much earlier than the AAG unit.

    http://www.weatherstations.co.uk/hydreon.htm

    My experience so far is that cloud detection is more important than direct water droplet monitoring to prevent the optical equipment from rain damage since the sensing area of capacitive/resistive/optical rain sensors is rather small, the telescope can get quite wet before a single droplet is detected by rain detectors, I consider these to be fall-back safety backup devices rather than a primary controller.

    I have mixed feelings about ACP as the observatory control software and was using CCD Commander for a while. Having a Paramount I am tied to having the TheSkyX running and ACP won’t work directly with TheSkyX’s automation interface. ACP requires Maxim and Focusmax so I have four separate applications running that often require updates to adapt to changes to Windows OS.

    The only function in ACP that made it attractive was the scheduler engine. With our UK weather, being able to ask ACP to image a target automatically and keep acquiring data at the best times, however many nights / weeks / months that might need until all requested data had been captured, was the ‘killer’ application.

    Software Bisque have been dropping hints that they are developing a new version of Orchestrate for TheSkyX that would offer many of ACP’s fuctions for the last four years or so but so far no news of progress or a release date and I couldn’t wait any longer so am committed to ACP, Maxim and Focusmax for some time to come. Certainly keeps you poor this hobby!

    Regards.

    William.

    #579336

    Hi William,

    How would you describe the relative merits of ACP and CCD Autopilot?

    Cheers

    Nick

    #579347

    Good morning Grant,

    My CCD and DSLR-Mount-Guide camera are all controlled via USB through the one cable.

    I have a Startech 4 port, powered USB hub which all the cables on that side of things are plugged into, on my Losmandy G11. I then have a Mutech USB Repeater Extension cable leading from this into the Whirlpool control-room. This cable is gold plated. I have the cable plugging into another Startech Powered hub.

    I have never had any issues.

    HTH.

    #579353
    William Bristow
    Participant

    Hi Nick.

    I can’t comment on CCD Autopilot, I did consider it and sent a couple of pre-purchase technical questions to CCD Ware that weren’t answered so I gave it a miss. It still has a busy forum though so I guess there must be quite a few users out there.

    I was using CCD Commander when I began automation and I found that very easy to use. The scripting interface is simple to understand and doesn’t require a degree in computer languages to operate. CCD Commander worked very reliably for a managed observatory operation. By managed I mean remotely operated or locally operated but manually administered on a daily basis. Once a target or sequence of targets was programmed CCD Commander could be left to acquire the data and close up the observatory at the end of a session or shut down and restart a session in the case of a weather event.

    I decided to move to ACP and ACP Scheduler mainly because of our fickle UK weather and by the limited unobstructed view afforded by my observatory location. I can only see around 55% of the hemisphere because of surrounding buildings and trees.

    I found with CCD Commander I would start a target sequence and then we would have four or five weeks of bad weather, by the time the weather was clear the target was no longer accessible and after a few years I ended up with a large number of folders of incomplete targets and I found it hard to remember which target folders needed completion on any given night as the year turned and a particular target presented itself’ again in favourable conditions.

    The basic ACP program has not that much on offer to differentiate itself from other automation programs. The price is higher than others and on technical ability alone the high price is not justified but the programs author considers ACP to be a service and not a product. If you run into problems during the initial software support period, or if you buy a subscription for ongoing support you will be given one-to-one help, either by remote desktop direct to your PC, Skype, or regular telephone and a dedicated user forum. In this respect ACP can be considered a package, software and support, and providing this level of one-to-one support is obviously expensive hence the initial high purchase cost and annual subscription fees for ongoing support and updates.

    If you have a fairly straight forward automation setup and can resolve most technical issues yourself, or are happy with a slower customer support then the basic ACP is hard to recommend on cost against technical ability, and bear in mind that ACP requires Maxim DL and FocusMax to function so the total software spend can be staggeringly large for an amateur observatory to carry.

    For me, the power of ACP is only revealed once you buy the add-on, ACP Scheduler. Scheduler will look at all the incomplete targets you have begun as well as new targets and decide which target is in the most favourable position for imaging and will start acquiring data as soon as conditions are right. If weather stops the acquisition before completion and a few hours later the weather improves then scheduler will look at the current best target from the outstanding list and continue on with that instead of returning to the earlier one which may no longer be ideally placed. And of course, you can override this sequencing at anytime and go for a target of opportunity, follow up on a supernova alert, whatever, then go back to the original target sequence. All the while Scheduler keeps track of what needs doing and manages the observatory.

    Since the move to ACP and ACP Scheduler two years ago I would say my acquired data and completed target rate has increased around 200% to 300%.

    Initial setting up of ACP is complex and a first time user will need to make extensive use of the help files provided with the program, they are well written though and I was able to set up ACP and start running without needing support, I had more problems with TheSkYX and my Paramount MX than with ACP.

    I don’t know if the above is of any help….it’s certainly a complex subject area and finding an automation product to suit your own needs can be difficult with so many competing applications on the market. Do make use of the free trial periods that most of the software vendors offer before jumping in to one package and be sure to determine what functions are essential for your automation project and which are wish-list items, it may help to narrow down the choice.

    William.

    #579358
    William Bristow
    Participant

    Hi Grant.

    One of the issues you will face with laptops (and most desktop PC’s) is that although you might have 3 or 4 physical UBS ports, on the outside of the laptop, inside the laptop all the ports are connected to a single internal USB root-hub which has an absolute limit on the data throughput from all the connected devices. I find that TheSkyX and my Paramount MX keep the USB root hub pretty busy as TheSkyX is continually polling the Paramount for Protrack drive corrections.

    One way around this is that your Dell Latitude E4310 has an ExpressCard 34 slot, just above the DVD drive. If you plug in a ExpressCard 34 USB extension card, you gain direct access to the PC main bus without having to go through the existing laptop’s USB Root Hub.

    ExpressCard 34’s are dying out now and becoming harder to find but some good quality brands still remain in stock with a few retailers.

    They were available with two or four additional USB2/USB3 ports but recently, amongst the better brands, I notice only two port cards are still available and only USB3 cards are still commonly stocked, two port USB2 cards are getting hard to find.

    The ExpressCard carries it’s own internal root hub. Some cards also have the facility to connect an external power supply for the USB devices which can be handy for power hungry devices such as some guide cameras.

    This gives you the option to put the low demand devices such as the GPS dongle, filter wheel, focuser etc on the laptop USB internal root-hub and your high demand devices like the Paramount and guide camera on an ExpressCard, or just put the GPS dongle on the ExpressCard alone. There are several ways to connect the devices about the laptops’ and ExpressCards’ available slots to keep the GPS dongle away from high demand devices.

    Sample link to a current Startech 2 port USB 3 ExpressCard34:

    https://www.ebuyer.com/338306-startech-2-port-usb3-0-expresscard-ecusb3s22

    And a sample link to a current Startech 2 port USB ExpressCard34:

    https://www.ebuyer.com/138357-startech-2-port-usb2-0-laptop-express-card-ec230usb

    The other option is to look for a second hand docking station for your laptop, that is if they ever made one, if you can find one that would usually give you another two/four USB 2 ports, again, directly connected to the laptops main bus and bypassing the laptops internal USB root-hub.

    HTH

    William.

    #579371
    Grant Privett
    Participant

    Yes. That makes sense. Had wondered about getting an additional USB socket on an Express card. Hadnt thought of the docking station though (I do have one somewhere). Might get a spare docking station while they are still available – I have a feeling the later Dell models also have a connector, but its a different format – will worry about that when I upgrade (I’m a fan of kit thats oldish, so that when it breaks it is not an expensive event – good for the stress levels.).

    Will grab a card and let you know how it turns out.

    #579356
    Grant Privett
    Participant

    Thats interesting. As my previous problem had been using a USB sound sampler on a shared port, I thought I should check again.

    So, I was out last night using a USB GPS dongle and NMEATIME2 to set my system clock to <0.005s accuracy, controlling a telescope from TheSkyX  (which uses a  USB to Serial converter to talk to a Paramount)  and a Starlight camera via a USB socket.

    The laptop I used was a Dell E4310 (Intel i5 at 2.4GHz with 4GB memory) which only has 2 USB sockets.

    I noticed that when anything was sharing a socket with the dongle, the NMEATIME2 correction timings became erratic – it assumes GPS  fixes from the receiver are evenly spaced I think. So, when I connected the telescope or when sharing with the CCD my timing precision was potentially off as the attached image demonstrates (the sharp change in the trace is when I connected the telescope). Not surprising I suppose, but the timesharing aspect clearly does have some an effect on other bus users. I imagine the impact will depend upon the nature of whats sharing the port and what laptop manufacturer/model you choose.

    I will try again tonight if (wonder of wonders) we get two clear nights in a row using a Dell D630 which has 4 USB ports and post the results here. Alas, I only have Dell laptops and so cannot say how this pans out with other machines. 

    #579429
    Grant Privett
    Participant

    Just a quick update. As you may recall, I found that using a USB on my Dell E4310 meant the speed of the other USB socket was impacted. In fact, when a GPS dongle was being used to set system time, it meant the error could jump from 2-3 ms to 20ms.

    To try to overcome this, it was suggested I try an Expresscard based USB port. I bought a Startech dual USB2 port card, but had to return it as it wasnt recognised on Win7 – even after 30 minutes with one of their helpful online advisors. So I tried instead a CSL dual USB3 socket Expresscard for £10. After loading the drivers that was immediately recognised. It  works  fine  with all the USB kit I tried. So I connected the GPS dongle up to that, hung a Paramount MEII tracking a satellite (22Hz tracking speed updates) on one of the laptop USBs and a Starlight 694 taking very short exposures on the other. Result can be seen above. For long periods the error was 2-3ms with occasional wandering to 4ms. Really not bad at all – plugging into the main bus made a big difference. Well worth the small installation effort.

    So, if timing is crucial to you, get a standalone network enabled time source and set up your own NTP server. But if 2-3ms accuracy is good enough, £20 for a GPS dongle and a CSL card will do the business.

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