DIO Boards

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Thread Starter

Curt Wuollet

Hi all

I am trying to find parallel DIO cards that would be acceptable to the automation market. There are hundreds available, but I want a basic low cost card to be the "base I/O" for the LPLC project. I want something that people can afford to buy and use to evaluate the first pass PLC code I am writing. The suggestion was made to use the parallel printer port and I almost did, but, I want something that can handle "real" automation levels of 24VDC in and out. I also entertained
the idea of using OPTO22 hardware, but, I think that's too expensive for someone who just wants to try out the code.

Later on, I can add the high speed DMA enabled DIO that will let us compete with anyone for speed, but for now, Im looking for something that won't scare off people who want to help test or develop.

What's out there ?

Thanks

Curt Wuollet, Wide Open Technologies


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I have boards from ComputerBoards Inc. in the past, and been pleased with them both as cost effective and functionally effective boards. They are generally compatible with National Instruments as well, so the user will have a choice between the "name brand" at higher cost and the "generic" computer boards for evaluation or lower-budget production use.

robm

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Phil Covington

Hi Curt,

I also have had good luck with Computerboards stuff. I've used their CIO-DIO24 (TTL) card which is $69.00. Unfortunately, if you get out of
their TTL level stuff, the price goes up steeply.

I don't know of any inexpensive DIO cards that handle 24VDC.

You might want to check out http://www.optimate.com/optilogic.htm and look
at their Ethernet I/O Optilogic stuff. The 4 slot RTU base OL4054 is $129, the 8 Point OL2208 10-30 VDC input cards are $39 each, and the 8 Point OL2109 5-40 VDC output cards are $45. As an alternative for outputs, they also have an 8 point OL2108 relay output card for $45 each. For $213 you can have an 8in/8out 24VDC Ethernet I/O system. They are Linux friendly also (email them for info). It would be hard to beat that price for the same 24 VDC capability in a Computerboards product...

Another interesting system is Automation Direct's (www.automationdirect.com) DirectLogic I/O with the Host Engineering Ethernet Base Controller
(www.hosteng.com). Host engineering will send you the source code for their EBC that can be compiled for Linux. The EBC is $249, a D2-03B base is $105, an 8 point 24VDC input module is $42, and an 8 point 24VDC output module is $46. An 8in/8out 24VDC Ethernet I/O system with these components will come to $442.

If you are going to go with TTL level stuff because of low cost, I would recommend just sticking to the PC's parallel port for I/O. The needed isolation modules to have 24VDC I/O can be hung off the port.

The Ethernet I/O stuff would be simple for people to hook up to try out the LPLC as it avoids the necessity of putting a board in their PC.

Even though I am primarily interested in W2K development right now (I have an opportunity to do some paid development in association with my day job <g>) I am trying to work with I/O that is easily used with Linux also, of which, the Optilogic and Host/Automation Direct products fit into that category. With Ron Gage's AB stuff, it is getting even easier.

Just some suggestions...

Phil Covington
 
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I've also worked with the Automation Direct ethernet (on the windows side) and found it to be very successful. In fact, we've had several OEM's standardize on it, based on ActiveX control wrappers we've written around Host's supplied code. I can also highly recommend it.

robm

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Curt Wuollet

Hi Phil,

Thanks, I hadn't seen these.
Looked it over, much cheaper than OPTO. I like the idea of Ethernet I/O too. Have you found out what the protocol looks like? They are kinda quiet on that. Unless I can find commodity boards with 24 V levels this may be the best bet. I want to stick with "industry standard" levels so the hardware can be used in "Real" apps.

Regards,

cww

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Greg Meister

Mr. Wuollet,

You might also look at the SIXNET ET-8DI2-8DO2-H. It supports Modbus/TCP as well as their proprietary protocol. List price is $495 US for 8DI and 8DO, a little more than the Optimate solution, but it does offer an open protocol. These units also have an RS-485 Modbus port so you can use the same module for testing a serial Modbus driver. Windows-based software for
configuring the module is supplied (sorry, no Linux software that I know of).

You can find out more at http://www.sixnetio.com/ethertrak/index.htm.

Greg Meister
[email protected]

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Hello,

Curt Wuollet:
> I am trying to find parallel DIO cards that would be acceptable to the
> automation market. There are hundreds available, but I want a basic low
> cost card to be the "base I/O" for the LPLC project.

I would suggest writing a `generic iomapped 8255' driver. That's the basic chip in a lot of these cards, including some with fancy replaceable 240V
opto or relay isolation modules.

> The suggestion was made to use the parallel printer port and I almost
> did, but, I want something that can handle "real" automation levels of
> 24VDC in and out.

If you write it as `generic ioport access', it's liable to come in handy anyway; besides, you can write it on the way to the 8255 driver.


Jiri
--
Jiri Baum <[email protected]>
Windows is not popular. Windows is *widespread*. Linux is popular.

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Curt Wuollet

Hi Jiri

I agree that we need one of these and it would be cut and paste from any one of a number of existing DAQ board drivers. I'll put it on my list. In fact, I'll bet the Linux Lab Project already has one that could be hacked to use a
header file or table for adress and setup for individual cards.

Regards

Curt Wuollet

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Curt Wuollet

Hi all,

On the Linux Lab Project site I found a char driver for the Computer Boards 8255 based DIO boards. These provide 48, 96, etc, digital outputs or inputs at ttl levels. The documentation is for guru's and scientists but, fairly complete. I will be the project contact and maintainer for this driver and will provide a heavily commented version and more verbose, if not better documentation as it is a good and reasonably simple example of a Linux device driver. When we have an I/O structure (ahem), this would be a good test vehicle. I also have in my hands, (making it hard to type) the low level protocol for the Optimation low cost ethernet IO. They are in process on a Linux driver for this product also. I am trying to get funding to buy a rack to test. The proto works something like Modbus, but allows you to send everything for one rack in a single transaction. It should be very fast if the rack processor can turn requests around quickly.

Who shall I send the CB driver to to check it in, was that you Jiri? I didn't ask about sharing the proto for the Optimation stuff, I'll ask them and if it's ok mail it to anyone who's interested. I have to retrieve it from the bit bucket, it's in MS word format and my mail filter sent it to the MS "folder" (/dev/null).

Regards

cww

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Hello Curt Wuollet,

> On the Linux Lab Project site I found a char driver for the Computer
> Boards 8255 based DIO boards.
...
> I will be the project contact and maintainer for this driver

So noted in the Maintainers file.

> Who shall I send the CB driver to to check it in, was that you Jiri?

You should probably get write access to the CVS - Dan Pierson is the person for that.

If you haven't set up CVS access yet (or don't want to), I'm willing to check things in for you...

(Note - I'd suggest calling it an 8255 driver, because lots of different brands use that chip, differing only in the number of them on the board and the I/O addresses, with the latter usually configurable anyway.)


Jiri
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Windows is not popular. Windows is *widespread*. Linux is popular.

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Hi Jiri

I must admit my ignorance, I haven't done group development for at least 10 years and my initial attempt at playing with the archive didn't jog my
memory in the slightest. I found the html interface particularly confusing and cvs never was very friendly to me. I will educate myself again, but in the meantime, I better send it to Dan so I don't hose anything up. I have write permission but thought better of writing anything. Perhaps Dan can point to the documentation for the web interface he's using.
I'll mail the driver off-list to save bandwidth. Thanks for updating the maintainer list.

Regards

cww

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Curt Wuollet:
> I must admit my ignorance, I haven't done group development for at least
> 10 years and my initial attempt at playing with the archive didn't jog my
> memory in the slightest. I found the html interface particularly
> confusing and cvs never was very friendly to me.

If you are just after the latest version, you can ignore most of the html interface:

http://www.linuxplc.org/cgi-bin/viewcvs.cgi/~checkout~/doc/cvs.html

(where "doc/cvs.html" is the filename within the project)

You can get directory listings, but unfortunately not the toplevel directory. So here's the toplevel directory: cvstest doc drivers philwil

So, for example, your code has been checked in under
http://www.linuxplc.org/cgi-bin/viewcvs.cgi/~checkout~/drivers

(Note: the links will sometimes send you back to the html interface; just
ignore it and edit the URL to the .../viewcvs.cgi/~checkout~/... syntax.)

> I have write permission but thought better of writing anything. Perhaps
> Dan can point to the documentation for the web interface he's using.

Ignore the web interface, use the command-line interface.

I don't see how you could set up writing into the repository via the web anyway. It needs too much state at the client end (it has to remember which
version you had before you started editing).


Jiri
--
Jiri Baum <[email protected]>
Windows is not popular. Windows is *widespread*. Linux is popular.

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