Fanless systems for Observatory use

[jase (Jason)]

Hi All,
I'd like to get some input into Fanless computer systems used solely for observatory control (focuser, imaging and guiding cameras, telescope and dome control, etc). The current set is a basic clone pc (no name brand) running XP SP3 in which I remotely control 180km away. For the most part, it works a treat considering its approximately two years old. The fan is starting to make a noise and dust is beginning to short the PCI wireless card, but other than that the OS and associated software has been rock solid.

Of late, I've been have some reliability issues in which has resulted in missing out of a couple of clear nights. I can only assume that the hardware is beginning to fail with lock ups etc. The obsevatory isn't the cleanest of places, insects, dust etc.

I've been looking at some industrial PC's to improve the reliability from a hardware perspective. Below are a few links I've been reviewing to give you an idea

http://www.ieci.com.au/products/nav....1&basecat1=256

http://www.quanmax.com/product/produ...FYIvpAodtQ_zrg

http://www.acrosser.com/products/Emb...lassid_98.html

You can get systems with a bucket load of USB and Serial ports which would be ideal as I'm running thin... especially considering I have a weather station, cloud/rain sensor and web camera to also connect, then all the other gear such as cameras, robofocus etc etc.

Has anyone had any experience with these systems for observatory controls or thoughts that would be of value?

Thanks in advance.

[jase (Jason)]

Also to tack on this. Anyone have experience with remote power management over IP. Suggestions please...thanks.

[GTB_an_Owl (Geoff)]

for your power management Jase, google "Iboot" (thats iboot)

geoff

[gary]

Originally Posted by jase

Hi All,
I'd like to get some input into Fanless computer systems used solely for observatory control (focuser, imaging and guiding cameras, telescope and dome control, etc).

Hi Jase,

You might also like to consider adding http://www.advantech.com/ to your search.
They have an office here in the north of Sydney and we have used one of their fanless
systems in a high up-time, mission critical application with success.

[jase (Jason)]

Originally Posted by GTB_an_Owl

for your power management Jase, google "Iboot" (thats iboot)

geoff

Thanks Geoff. Did some research, seems a PDU is also available so I think I'm all set - http://www.zantech.com.au/power/reboot/cdu.html. Though a larger PDU is likely to have a fan that will suck in dust etc. aarrggg. The Iboot as you suggest, even have a feature that if the IP stops responding to a ping, it will drop the power. Nice feature, could be dangerous. Thanks for the insight. I'll make some enquires. Cheers.

Originally Posted by gary

Hi Jase,

You might also like to consider adding http://www.advantech.com/ to your search.
They have an office here in the north of Sydney and we have used one of their fanless
systems in a high up-time, mission critical application with success.

Cheers Gary. Had not heard of them. Will investigate further to see what is on offer.

[citivolus (Ric)]

While you are at it you may want to consider the use of a solid state hard drive, to reduce your mechanical failure chances to zero. Electrolytic capacitors in the power supply would likely be your primary source of failure in such a configuration, so depending on your capacity overhead, you could likely go several years without replacing components.

[loc46south (Geoffrey)]

Hi - I am running some tests at present trying to set up a remote observatory powered by solar - unit is controlled by an EEE PC (not the laptop version by a stand alone PC verion) 80gb SS disk. Its running a C9.25 on a G-11 gemini with either a Moonlite or OPTEC TCF-S and a SBIG ST8 or ST2000XCM - Software CCD Commander/SKY6 pro/Focus Max/CCDSoft 5 plus Ramin 3 server. For testing the unit is being controlled from the Radmin server - the PC has no monitor attached. Peak load is 7 amps - running average 3.5amps to 4 amps. If you want further details PM me.

Geof Wingham

[acropolite (Phil)]

Anyone have experience with remote power management over IP. Suggestions please...thanks.

Jaycar have a 4 relay IP switching kit for under $100. The switcher has it's own built in web server. A web search shows the company that makes the kit has various assembled switching solutions available including rack mounted with standard PC power outlets.

I have one of the jaycar kits, it's just 2 boards, no assembly, simply add 5V Plugpack and connect the 2 modules together with the supplied cord. The build quality of the boards is excellent.

The switcher has 2xNO and 2xNC relays, this should be easily changeable with a bit of simple soldering. The switcher works as expected although at this stage I have been unable to send login details and a switching command together and have the unit switch as per the documentation(the login bit is rejected). If I log in first then it's no problem, so for remote use it wouldn't be any big problem. The documentation is typical chinglish, but it's adequate to get the thing working.

Here's a link to the manufacturers site and a link to the IP power 9202 user manual.

[gary]

Originally Posted by citivolus

While you are at it you may want to consider the use of a solid state hard drive, to reduce your mechanical failure chances to zero. Electrolytic capacitors in the power supply would likely be your primary source of failure in such a configuration, so depending on your capacity overhead, you could likely go several years without replacing components.

Hi Ric,

Though solid state drives (SSDs) can provide wonderful solution in many applications,
one needs to be aware of the inherent limitations of FLASH memory, which are
commonly used in many modern SSD's. FLASH sectors only have a limited number of
write cycles (typically in the order of 100,000) before the sector fails. Firmware
integrated within the disk controller or a FLASH-aware file system can mitigate
the wear by distributing writes to disk across the disk, what is commonly referred
to as 'wear-leveling'.

Nevertheless, when using SSD's that employ FLASH memory in a mission critical
application, one needs to perform some profiling of the number of write cycles
that occur when the target OS and applications are installed and running.

Applications that perform large numbers of writes can result in SSD drive
mean-time before failure (MTBF) rates that are lower than conventional magnetic
drives.

In other words, without profiling the application's disk requirements, using
SSD's may result in a situation where the failure rate can be made worse.

Best Regards

Gary Kopff
Mt. Kuring-Gai

[Moon (James)]

How about a Toughbook?
It has the advantage that the internal battery can act as a mini UPS.

[jase (Jason)]

Thanks everyone for their suggestions. It has given me plenty of leads to investigate. I wasn't aware a wifi based IP power management solution even existed! Awesome. SSD is beyond my needs, but the technology has it uses.

Thanks again.

[Bassnut (Fred)]

Jase

Your right on the money there with avoiding fans, I found ALL fans in my remote system died with dust/corrossion. EXCEPT, the PC, oddly. I looked into fanless industrial PCs, but they are expensive and you run the real risk of an Astro app not running on it and the chances are much reduced of ferriting out a solution on unique hardware/OS version.

I ended up with a standard dual core desktop and it was very reliable, didnt hick up once, unlike all the other stuff. The fan runs very slowly and quietly, which may have helped reliability. IMO, you need to worry about fans on everything else rather than the PC and just stick with a standard known desktop.

I used this IP addressable power board, and it was very solid/reliable http://www.digital-loggers.com/lpc.html, and cheap, only US$100 odd ! (works on 240v, but the sockets are US, a small irritation). But , as with all the gear, the fan died.

[jase (Jason)]

You nailed a fear I have with specialised hardware, but I think for the most part the hardware would be transparent to the astro data acquisition apps like focusmax, pinpoint, maximdl, blah blah. If it wasn't transparent, then the OS isn't doing its job IMO. The problem I have is the current system is a tower case. The CPU fan gets choked up with considerable dust. Over time it falls down onto the PCI wireless adapter causing me grief shorting things out. There's always a cheap or expensive way of solving this. The PC in the Obs is never turned off unless there's a power failure as its also used to log weather station information from the Davis Vantage Pro and Weather Envoy data logger.

Looking at some of great suggestions here has given further insight. I think I'm better off with a system that it's external case/enclosure is one giant heat sink instead of a fan operated unit. Some operate on 48VDC would may also lend itself well with future solar power plans, but I'm not pushing for a "green" observatory as yet.

I should note that I don't use this system for processing. Solely data acquisition.

[Bassnut (Fred)]

Remember the IP adressable power board is connected directly to the modem with its own web interface, so you can leave the PC off during the day and just turn it on at night via the power board. In hindsight, I think having everything off during the day is a wise move. The temp swings and weird overloaded-buffer etc faults that occured with being on 24/7 ment a regular power reset anyway. You will find the times you are able to image (and the PC is on) are relatively wind/dust free and your PC will last much longer. Has the weather station got its own IP interface direct to the modem?.

The big bonus with battery DC supply is you can have OBs close on mains power loss, so why not use it for the PC too, but I think a UPS to a standard PC is cheaper. Even if you need to replace the PC every 3 years or so, its potentially less grief and expense over custom/specialised power supplies/fanless PCs.

Interestingly, PMEs can randomly slew to hard stop after 4 hrs or so idle if left on 24/7, they need to be homed every 3hrs or so to stop this.

[jase (Jason)]

Modem? No can do I'm afraid. Only way in and out is via the satellite connection. Rural phone lines don't hold up to data comms, at least not my service where the local exchange has been converted from tin shed/outdoor toilet. Interference from electric fences renders it useless. Providing the device can be allocated an IP and will forward Ethernet frames either via a cabled or wireless connection in an autonomous manner, I'm sorted.

I agree with you, it would be wise to shutdown the gear during the day. The Weather Envoy logger will store 8 days of data at the configured sampling period before it overwrites old records so the PC would only need to be brought up once every 8 days to keep the history. The envoy has a battery backup should mains be lost. I'll work on the remote power management with the leads others have provided. Appreciate the input Fred.

[Kal (Andrew)]

Another option with a pc is to have one with a properly implemented fan cooling system. Two simple rules will accomplish this. 1: Have more fan power 'blowing in' rather than 'sucking out' to maintain a positive air pressure inside the case (else the dust gets sucked in through every crack it can find, around your optical drives etc), and rule 2: have every intake fan covered with a removable cleanable dust filter. Make sure you clean the dust filters occasionally.

As long as you build your own system it is easy enough to cover these rules and have a computer that will operate fine in a dusty environment.

[Bassnut (Fred)]

I ment by "modem" any net connection. How do you find satellite for OBs control?. I understand satellite has so much lag that it makes live control functions awkward?. GRAS used 3G for control and satellite for image uploads, probably a bit over the top for personal use.

[citivolus (Ric)]

Another option is to schedule your system to start up at a fixed time every arvo (via the BIOS options), and simply shut it down after your observation run. That would avoid operation during the heat of the day, and reduce dust intake by at least 50%.

[GTB_an_Owl (Geoff)]

gentlemen - there is nothing in the text books that says a computer must operate with the motherboard on the bottom or the side

the problem of dust can be minimised simply by turning it upside down

or putting it in a controlled environment cabinet or the like

geoff