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Crazy Question - What's The Difference Between the PMC8 and a Mini- Computer? #EXOS2 #TECHNICAL #OpenGOTO


Darryl Ellis
 

That does help Robert.  I appreciate it.

So now I won't feel guilty when I invest in yet another device for my AP setup, lol. 

Thanks,

Darryl
--

DHEllis59, Dover, DE

Astro Tech RC 6 w Pegasus Focus Cube and QHY10 OSC Camera
Orion ST 80 Guidescope and QHY 5 III 290c Guide Camera 
Explorer Scientific EXOS GT 2 With PMC Eight Controller,
ES 16" Truss Tube Dobsonian and Orion XT8 with Nexus II DSC via Sky Safari Pro,
Celestron Luminous 31mm, Meade MWA 21mm, 15mm, 10mm, and 5mm EPs
Celestron Skymaster 15x70
and 15x25 binoculars
20/20 or better vision in both eyes due to recent cataract surgery!!!
"The LORD by wisdom founded the earth, By understanding He established the heavens" - Proverbs 3:19


Darryl Ellis
 

Wow, that looks the business Jennifer.  Love the dual monitor setup as well.

Yeah, I bought a mini computer off of Amazon which worked well.  It had a defective power connection so I returned it.  I plan on replacing it at some point, but got distracted and ended up buying a new to me camera.

I'll have to look into the Optiplex.

Thanks,

Darryl
--

DHEllis59, Dover, DE

Astro Tech RC 6 w Pegasus Focus Cube and QHY10 OSC Camera
Orion ST 80 Guidescope and QHY 5 III 290c Guide Camera 
Explorer Scientific EXOS GT 2 With PMC Eight Controller,
ES 16" Truss Tube Dobsonian and Orion XT8 with Nexus II DSC via Sky Safari Pro,
Celestron Luminous 31mm, Meade MWA 21mm, 15mm, 10mm, and 5mm EPs
Celestron Skymaster 15x70
and 15x25 binoculars
20/20 or better vision in both eyes due to recent cataract surgery!!!
"The LORD by wisdom founded the earth, By understanding He established the heavens" - Proverbs 3:19


 

Darryl,
 
Nothing is missing :-)
 
Your PMC8 is built around the Propeller chip that Jerry described, and it is a dedicated real-time processor.  I'm not aware of anything else like it on the market.  No, it's not a general-purpose chip, but it's a fine choice for what he needed it to do.
 
On top of that, the motor control functions are encapsulated behind an API (the PMC8's control language).  So whatever astronomical control program comes down the road, now or later, just write a driver to talk with that documented API and you're good to go.
 
So yes, the new purchaser does need to have a separate computer to act as an executive for the PMC8, whether for visual or AP, but IMO that's a feature, not a bug.  It preserves independence and versatility.  Today I use a Win7 laptop and ASCOM for AP, but when that runs out of gas for me, I'll probably end up with a Raspberry Pi and INDI - based solution.  And when someone comes up with yet another astro-gadget-management platform, that will probably work, too - because the PMC8 converses with its control programs but is not entangled with them.

Hope this helps...
 
- Bob  
 
--
Mounts: ES PMC-8 EXOS2
Scopes: SV 102EDT, ZWO 60/280 Guide
Cameras:  Nikon D5300, Altair GPCAM2 290M
Software: ASCOM, CdC, AstroTortilla, BYN Pro, Sharpcap, PHD2
Computer:  Thinkpad x230, Win7Pro/64


Jennifer Shelly
 
Edited

Daryl:

There are many mini PCs out there.  Some are in the form of a kit and others are user ready.  Some have a Windows OS others have Raspberry Pi.  


I ultimately decided on a Dell Optiplex Micro PC with 6 core Intel processor and Windows 10 x64 OS. The system works very well for me.  It also has enough processing power to run PixInsight.  I have a a little desk on wheels that I have the Dell Optiplex mounted underneath.  I just roll the cart out to my porch for an imaging session.  Previously I was using a gaming laptop and the Optiplex is much better.   Essentially it is like a laptop on steroids without a monitor, mouse, or keyboard.  

Below are some pictures of my setup.




--
Sincerely,

Jennifer Shelly
AstroPorch, VA

Mounts
: ES PMC-8 G-11, ES PMC-8 EXOS-2
Scopes: ES ED127 FCD-100, ES Levy Comet Hunter, ES N208CF, QHY Mini Guide Scope, Solomark F60 Guide Scope
Cameras: QHY600M, QHY128C, QHY168C
Misc: MoonLite CFL 2.5 / High Res Stepper / V2 Mini Controller, Baader SteelTrack NT / SteelDrive II, Baader UFC, Optolong 2" L-Pro / L-eNhance, QHY CFW3-L, Baader 2” LRGBSHO CCD
Imaging Software:  NINA, APT, SharpCap Pro
Processing Software: PixInsight, Lightroom, Premiere Elements


Darryl Ellis
 

Jerry,

As always i appreciate your responsiveness and detailed, this one being somewhat over my head, answer, lol, but I get the point. 

I was just wondering because a lot of the components sounded familiar.

Also, I have been considering getting a mini computer or something similar to use with my mount, but it just felt redundant.

Darryl


--

DHEllis59, Dover, DE

Astro Tech RC 6 w Pegasus Focus Cube, 
QHY10 OSC Camera
Orion ST 80 Guidescope
QHY 5 III 290c Guide Camera 
Explorer Scientific EXOS GT 2 With PMC Eight Controller,
ES 16" Truss Tube Dobsonian and Orion XT8 with Nexus II DSC via Sky Safari Pro,
Celestron Luminous 31mm, Meade MWA 21mm, 15mm, 10mm, and 5mm EPs
Celestron Skymaster 15x70
and 15x25 binoculars
20/20 or better vision in both eyes due to recent cataract surgery!!!
"The LORD by wisdom founded the earth, By understanding He established the heavens" - Proverbs 3:19


Jerry Hubbell - Explore Scientific VP Engineering
 

On Sat, Jun 27, 2020 at 10:55 PM, Darryl Ellis wrote:
Help me understand.

HI Darryl,

The PMC-Eight Control System is a dedicated instrument designed to control a two-axis stepper motor system. There are actually 2 microcontroller chips in the PMC-Eight system. These are not general purpose processors like what is on a Single-Board Computer (SBC) system. The main microcontroller (processor) is a Parallax Propeller 8-core microcontroller. This processor does not run an operating system. There are 8 separate tasks that each run on a dedicated processor and has access to their own memory space and share information amongst processors through a global memory system. The firmware I created to command and run the motors is written in the proprietary Propeller spin language and also in Propeller assembly language. These languages allow me to control the hardware IO pins directly. You can think of a microcontroller as a signal generator that speaks directly to other hardware such as the stepper motor driver chips used in the PMC-Eight, the serial interface, and USB interface driver chips. I designed and create the output signals from the Propeller chip in firmware to run the other hardware on the PMC-Eight circuit board.

The other microcontroller used in the PMC-Eight control system is the dedicated WiFi processor (microcontroller). The Microchip RN-131 WiFi module is used in the large board Model 2A PMC-Eight system (G11, EXOS 2), and the Espressif ESP-WROOM-02 is used in the Model 1A PMC-Eight system (iEXOS 100). The WiFi processor also has firmware that we load and configure that provides the wireless network protocol stack and serial interface we use to transmit data in and out of the Propeller processor. 

What you are asking is why can't the PMC-Eight operate like an Arduino, or Raspberry Pi? The answer is that these processors are not general purpose computers that run an operating system the way we have them configured in the PMC-Eight system. Having said that, the ESP-WROOM-02 can be configured to run the RTOS operating system if one were to load that firmware into the processor. I did not choose this configuration as all we require is to run a wireless protocol stack and serial interface to the Propeller 8-core microcontroller. The Propeller chip has access to only 64 KB of memory space (EEPROM) with 32 KB of firmware loaded from the EEPROM into system RAM (32 KB) when booted. The ESP-WROOM-02 has 4 MB (32-Mbit) of memory space (EEPROM) to load programs and firmware and provides a file system to store data. This is a more sophisticated processor that can approach but not quite be a general purpose computer in operation. 

If you own an iEXOS 100 system, you could reprogram the ESP-WROOM-02 WiFi module to include the RTOS operating system and build applications install the network stacks and also run a webserver to provide an interface HMI on the network. We have not (as yet) worked on this type of control interface for the PMC-Eight control system. We are currently researching and developing these and other systems that use SBC's and the WiFi modules capabilities but we have not announced any plans for future products based on this technology. We are still ramping up our capabilities in these areas. 

Finally, we provide the documentation and links for our customers to pursue this work for themselves and share as they see fit with the OpenGOTO Community of PMC-Eight customers.

I know this is a bit long, but I wanted to explain to everyone what the system is actually capable of and how we provide "margin" for future capabilities and future improvements.

Thanks
 
--
Jerry Hubbell
Vice President of Engineering

Explore Scientific, LLC.
jrh at explorescientific.com

www.explorescientificusa.com
1010 S. 48th Street
Springdale, AR 72762
1-866-252-3811

Author: Scientific Astrophotography: How Amateurs Can Generate and Use Professional Imaging Data
             Remote Observatories for Amateur Astronomers: Using High-Powered Telescopes From Home


Mark Slade Remote Observatory (MSRO) IAU MPC W54 Equipment
Wilderness, VA
Mounts
: ES PMC-Eight G11 + Telescope Drive Master (TDM)
Scopes: ES 165 FPL-53 ED APO CF, ES 102 FCD100 ED APO CF
Cameras:  QHY174M-GPS + FW, QHY163C
Misc: 3-inch 0.7x Focal Reducer Field Flattener, Filters: Luminance,
Red, V-band Photometric, Diffuser, 200 lpmm Spectral Grating

Software: MaxIm DL 6, Cartes du Ciel, Astrometrica, AstroImageJ, AutoStakkert!


Darryl Ellis
 

Hi All,

After going through the Programmers Reference Guide looking for solutions to an issue I have with switching between serial and wifi modes, it bought to mind one of the main reasons I invested in this mount and the PMC8; I was hoping it was going to be more like using a PC with wifi than an Hand Controller.  I always felt like hand controllers were limited though at times I admit I miss having one.  Then there are systems out there like the ASI Air Pro, Prima Luce, Raspberry Pi, etc.  There are mini pc's and other such gadgets. 

Then there is the PMC8, Precision Motor Controller with its 8 processors,computer processor and memory system, motor drive system, and communications interface.  It even has it's own Programmer's language.  Now I'm no computer technician, programmer, or engineer.  However, I have been a functional user of computers since the 80s and have done some pretty interesting things with them.  The PMC8 sounds like a computer to me! 

What am I missing?  What keeps it from being used like a mini computer, or something that I could load programs onto like ExploreStars, PHD, APT, CDC, etc.?  What would it take for the PMC8 to function like/compete with an ASI Air, Pima Luce, or even a PowerwBox? 

I just feel like it's a great idea with a lot of potential, but something is missing.

Help me understand.

Thanks,

Darryl

DHEllis59, Dover, DE
Explorer Scientific 102mm CF EDT 
Astro Tech RC 6 w Pegasus Focus Cube,
Orion ST 80 Guidescope
QHY 5 III 290c Guide Camera 
Explorer Scientific EXOS GT 2 With PMC Eight Controller,
Orion XT8 with Nexus II DSC via Sky Safari Pro,
Celestron Luminous 31mm, Meade MWA 10mm, and 5mm EPs
Celestron Skymaster 15x70 binoculars,
20/20 or better vision in both eyes due to recent cataract surgery!!!
"The LORD by wisdom founded the earth, By understanding He established the heavens" - Proverbs 3:19