Shop OBEX P1 Docs P2 Docs Learn Events
What I've been working on- PropPLC — Parallax Forums

What I've been working on- PropPLC

crgwbrcrgwbr Posts: 614
edited 2008-01-17 01:12 in Robotics
If you've noticed, lately I haven't been posting around the forums as much as I normally do. Main;y, this is because I've been busy with a new project: The PropPLC. Unfortunately, it was designed for a private company's use, and isn't for sale. I also can't post any schematics or much data about it. But I can share a little info about it with you, as well as a few pictures.
It's similar in design to the Basic Stamp PLC. It's features include:

-Propeller Multi-processor (in PropStick USB form)
-4 optically isolated digital inputs (active high)
-3 quadrature encoder inputs (data lines are pulled up to 3.3v for use with open collector output encoders)
-12 optically isolated digital outputs (12v active high, 500mA maximum current)
-USB Stick Data Logger
-RTCC
-FT232R USB with Mini-USB port (programming and PC coms)
-direct terminal block access to pins 28-31
-small foot print (4.5 inches square)


Let me know what you think

Regards,
Craig

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
My system: 1.6 GHz AMD Turion64 X2, 4GB DDR2, 256MB ATI Radeon Graphics card, 15.4" Widescreen HD Screen

I have a duel boot of Ubuntu Linux and Windows Vista. Vista, because it came with the PC, Ubuntu because I like software that works.

"Failure is not an option -- it comes bundled with Windows."

Use The Best...
Linux for Servers
Mac for Graphics
Palm for Mobility
Windows for Solitaire
IMAGE_178.jpg
1280 x 1024 - 318K
IMAGE_180.jpg
1280 x 1024 - 248K

Comments

  • UnsoundcodeUnsoundcode Posts: 1,532
    edited 2007-12-28 17:14
    Hi Craig, your PLC is a nice looking unit. Is the program Spin or assembly. I realize this was made to a customers specification and wondered if you planned to make more for other potential customers. This would be really great in a modular form and give you the option to change the ratio of inputs to outputs and the type of inputs while still retaining a standard CPU card. Then again custom built units do keep the size down. A HMI with a touch screen added to this would make an impressive controller at a fraction of the cost of the main brand PLC's.

    Nice work

    Jeff T.
  • bennettdanbennettdan Posts: 614
    edited 2008-01-07 04:47
    crgwbr,
    The "seimens" PLCs S7-300 and S7-400 series PLC you are have multi very fast micros inside and they are not just limited to Ladder logic they can be programmed in Statement logic, function block and ladder logic.. Now the other main line of PLCs are the AB Allen Bradley PLCs that can be programmed with all three ways like the siemens PLCs they also have the ablitity to be programmed in Visual Basic.. They also have muti communication protocols that are very robust and stand up to many harse conditions.
    I do like the Prop and a PLC would be a good project but their are some many different applications a PLC has, it would take a long time to create all the interfaces in the industrial world the "Big Three" would pass you by...
    One thing if you are interested in PLC their is a company called automationdirect.com they have some small modular PLC that are very nice units I have used them in many projects in the past..
  • QuattroRS4QuattroRS4 Posts: 916
    edited 2008-01-15 19:47
    crgwbar,
    Just wondering about dedicated analogue inputs .. any planned .. Also will the final version have good ground plane and Input and I/O filtering ? LC types for example .. Just saying this as I have quite a few Props in industry on dedicated P.C.B's and had a few minor issues with inductive loads and PSU transients .. What is the proposed application environment ?

    JT

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'Necessity is the mother of invention'
  • crgwbrcrgwbr Posts: 614
    edited 2008-01-16 02:49
    I'm planning a ground plane for the next revision. Because of the amount of capacitance in the power supply system, in addition to the linear regulator supplying power to the Prop, I don't think that voltage drops should affect it that much. As far as I/O filtering, I guess I'm not quite sure what you mean. I already have optical isolation on both inputs and outputs (except for the 3 open collector quadrature encoder inputs). The application for these particular boards have to do with position sensing on a tool support arm. Here's a link to the company it's for.

    Regards,
    Craig

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    My system: 1.6 GHz AMD Turion64 X2, 4GB DDR2, 256MB ATI Radeon Graphics card, 15.4" Widescreen HD Screen

    I have a duel boot of Ubuntu Linux and Windows Vista. Vista, because it came with the PC, Ubuntu because I like software that works.

    "Failure is not an option -- it comes bundled with Windows."

    Use The Best...
    Linux for Servers
    Mac for Graphics
    Palm for Mobility
    Windows for Solitaire
  • OzStampOzStamp Posts: 377
    edited 2008-01-16 04:54
    Hi crgwbr..

    How do you reference the arm ..?
    When you trun the power off do you loose the present position ...??

    we did something similar recently and used Renishaw abo(expletive)e encoders with SSI encoder interface.
    protocol used is simple.. and lightning fast with the Propeller..

    Ron mel oz
  • crgwbrcrgwbr Posts: 614
    edited 2008-01-16 13:52
    Because of cost restrictions, we used a 2500ppr rotary encoder at the Z axis joint (the only axis we need to measure). Basically, when you turn the machine on, it retrieves 6 different depths from eeprom (these are programmed via USB link to a python GUI). Then the user sets a zero point for each of these positions. Then, as the user is tapping holes or something else like that, when the arm reaches that depth, the machine either reverses the power tool (for tapping) or stops the power tool (for chamfering, etc). So far, it seems to be accurate to a few thousands. Starting soon, I willb doing a 3axis version on one of the linear arms. I'll keep you posted

    Regards,
    Craig

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    My system: 1.6 GHz AMD Turion64 X2, 4GB DDR2, 256MB ATI Radeon Graphics card, 15.4" Widescreen HD Screen

    I have a duel boot of Ubuntu Linux and Windows Vista. Vista, because it came with the PC, Ubuntu because I like software that works.

    "Failure is not an option -- it comes bundled with Windows."

    Use The Best...
    Linux for Servers
    Mac for Graphics
    Palm for Mobility
    Windows for Solitaire
  • Rob7Rob7 Posts: 275
    edited 2008-01-16 23:50
    Craig,
    Great job on your PLC.
    I have made a PLC with the BS2 and have been inproving on it every year for my holloween castle.
    I never thought of using the propeller for that ?
    Great job.
    Will you be making pc boards for this for other to use ?

    Rob7
  • crgwbrcrgwbr Posts: 614
    edited 2008-01-17 01:12
    crgwbr said...
    Plans are already in the works for a stackable version. Basically, the CPU card would be at the bottom, then I/O cards would stack directly on top and plug into a big header.

    Yep, but don't expect them to be released soon. It will be mid-summer at the earliest.

    Thanks for your interest,
    Craig

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    My system: 1.6 GHz AMD Turion64 X2, 4GB DDR2, 256MB ATI Radeon Graphics card, 15.4" Widescreen HD Screen

    I have a duel boot of Ubuntu Linux and Windows Vista. Vista, because it came with the PC, Ubuntu because I like software that works.

    "Failure is not an option -- it comes bundled with Windows."

    Use The Best...
    Linux for Servers
    Mac for Graphics
    Palm for Mobility
    Windows for Solitaire
Sign In or Register to comment.