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  1. #81
    Registered jhovel's Avatar
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    Thanks Bill!
    I'm doing some other PCBs at the moment and might add this one on the corner of a sheet.... I'll have a go at adding the PSU components in the bottom left corner.
    Cheers,
    Joe

    Joe in Aus


  2. #82
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    I'll have a go at adding the PSU components in the bottom left corner.
    If you succeed, be sure to post the results here so other can benefit

    Bill

    Bill


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    Registered jhovel's Avatar
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    OK. Haven't done anything 'electronic' over the weekend after all, but had a go at the 'mechanicals' for my set-up.
    A close look at my Fujitsu Pen computers and my milling machine discovered a relatively easy way to mount it: a simple steel angle frame and a quickly bent top clamp would mount the PC securely and there was a 5/8" thread in the top of the mill (perhaps for a difting eye or hook?) which lent itself to be used as a mounting point - out of the way of coolant spashes and accidentally flying tools or work pieces
    Here are a couple of photos. Nothing is cleaned up or painted yet - just testing function.... No connections or anything yet, and only the X-axis scale mounted so far at the very bottom of Photo 3 - no cover made or fitted yet). The images show the 'Demo Mode' of Bill's Vernier Display.


    Cheers,
    Joe

    Joe in Aus


  4. #84
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    Finally made another step forward: revised the PCB layout for this DRO controller, removing the redundant components and adding the supply regulator parts to the board.
    I've now etched and drilled a prototype, ready to add components (not all here yet). I even managed to get myself a chip programmer and with Bill Todd's help via e-mail got the PIC progammed.
    Next step is to complete the board and test it and mount the remaining two scales (hacked vernier calipers) on the milling machine.
    THen wire everything up and report back

    Attached Thumbnails Attached Thumbnails PIC based DRO-pcb-jpg   PIC based DRO-pcbtracks-jpg   PIC based DRO-drilling_pcb-jpg  
    Joe in Aus


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    Well, I have finally completed the assembly of the DRO PCB and found a small mistake: R6 is shown connected to the wrong hole in the previous post. It's lower leg should be connected to the spare hole between C1 and D3 on the +3.5V bus. I'll post an updated image once I've established everything is working.
    Still having some trouble getting my scales to behave. Will post once this is sorted.
    Boy are the connectors on the scales tiny! Much too small for my big fingers, tools and soldering iron! Working under a strong magnifying glass is the only way for these old eyes to even get close....
    Cheers,
    Joe

    Last edited by jhovel; 02-03-2011 at 01:44 AM.
    Joe in Aus


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    Well it's been a long time since I visited this thread... It looks as though a few more people have taken interest in this.

    I had to put my hobbies on hold for quite some time but am now back into the process full swing...

    I wanted to mention that Microchip has since come out with a very interesting little chip that would be fantastic for this as a replacement to the 12F765 being used. The chip is the 12F1822 and you can read about it here. It has an internal 32MHz oscillator as well as hardware USART.

    Anyhow I just wanted to mention it as it should make life a little simpler for anyone wanting to start from scratch on the project. I will be starting in on it again fairly soon using these chips along with a larger chip running the "interface" to a larger LCD for a stand-alone solution. Or I may use some of the usb/serial 7 segment displays I just finished.



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    The chip is the 12F1822 and you can read about it here.
    Interesting that hardware SPI would make chaining a number of these together a whole lot easier .

    BTW Prompted by Joe (in Aus) I've updated the VB program and have added another vernier/scale type to the PIC code (this is an odd one I found, the scale displays fractions of an inch as well as decimal and uses a fixed rate BCD format protocol).

    The VB app is now scalable so will fit different window sizes. I've added linear speed (in inches per minute or mm/s) for each axis and it can display a Tacho/rev counter with the ability to set tool diameter thus giving tool cutting speed (requires a different PIC code and a opto sensor - see zip file)

    If any one is interested, I'll package it up into an installer exe. (see attached)

    Attached Thumbnails Attached Thumbnails PIC based DRO-vernier-1-2-03-jpg  
    Attached Files Attached Files
    Last edited by BillTodd; 06-26-2011 at 01:42 PM. Reason: attaching the correct file this time :)
    Bill


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    Hi Bill.
    Thanks for the update.
    I still haven't got anywhere with my DRO - I can't get it to recognise the scales at all. I kind of gave up a couple of months ago in frustration.
    In the process of resoldering and replacing various resistors and transistors, I destroyed a couple of tracks as well.....
    I'll have to start from scratch and do new pcb design. I'll make the tracks a little fatter, the gaps a little wider and may use in-line scale connectors or in-line headers for the scale connectors. The staggered connectors - or rather the tracks running between them did mine in.... I would really not mind if the whole board is a bit bigger. I'd rather find a bigger enclosure than work under a microscope for the entire assembly

    PS: As you know, I also have a 24" long scale - I have since found a description of it's 21-bit code! I'll e-mail you the details.

    Joe in Aus


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    Quote Originally Posted by jhovel View Post
    Hi Bill.
    PS: As you know, I also have a 24" long scale - I have since found a description of it's 21-bit code! I'll e-mail you the details.
    Please do

    Bill


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    As to using the PICs with quadrature encoder, I'm sure the little 8 pinners I've used lack the necessary hardware (you'd need a couple of fast counters to ensure no pulses were lost). The ones to use would be the dsPIC devices like the 30F4012 (?) which have the quadrature hardware inside.
    Has anybody mentioned the encoder interface chips from USDigital yet?

    ( US Digital | Products » Interfaces » ICs )

    I often have to do low-volume encoding based systems in microcontrollers, and I end up using these chips a fair amount, particularly the LFLS7366R standalone encoder counter to SPI chip.

    They're useful when you need one controller to monitor several channels, especially if some channels can have high count rates. You set 'em up and then just come back and poll them once in a while.

    I find they're much more cost-effective than the old Agilent chips.

    You can also buy all these chips direct from their original manufacturer, LSI, but USdigital stocks them and sells them in small quantities and they're quite hobbyist-friendly.

    Also, thought it's off the PIC subject, since some people are talking about PC based solutions, USDigital also offers an encoder... dongle, I guess, that allows fairly direct plumbing from a quadrature encoder to a USB port.

    ( US Digital | Products » QSB Quadrature to USB Adapter )



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    I often have to do low-volume encoding based systems in microcontrollers, and I end up using these chips a fair amount, particularly the LFLS7366R standalone encoder counter to SPI chip.
    That's a very useful chip

    Bill

    Bill


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    Smile

    Quote Originally Posted by BillTodd View Post
    I'm not actually reading encoders. I'm decoding the digital data outputs of those cheap Chinese digital calipers (see :examples here). To keep my circuit simple, I'm using the PICs onboard comparitor and reference to convert the low level (~1.5v) signal to one that the PIC can read.

    This circuit is of a single device reader powered by the serial port.



    The LEDs (D1,2,3) limit the voltage to about 1.2v when the PIC drives the scale's inputs.
    Hi Bill, Interesting Thread, But will you please repost the image..... I found a broken link here.

    Also if can you please refer any PC Interface for Magnetic Linear Scales.



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    Hi Bill, Interesting Thread, But will you please repost the image..... I found a broken link here.
    I'm not sure which image you mean? which message number?

    Bill

    Bill


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    Red face

    Quote Originally Posted by BillTodd View Post
    I'm not sure which image you mean? which message number?

    Bill
    Hi Bill, i think i have overlooked your attached link before. i was just looking for your circuit.

    Also will you please suggest me any thing good for my Magnetic Scales. Can I read the same with your Circuit.

    Last edited by aadityadengle; 01-26-2012 at 02:43 PM.


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    Quote Originally Posted by aadityadengle View Post
    :Also will you please suggest me any thing good for my Magnetic Scales. Can I read the same with your Circuit.[/COLOR][/B]
    Do the magnetic scales have a display (read-out) or do the magnetic scales will output a quadrature ttl level signal on two wires?

    Bill


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    Yes!!!! Phase A & B with TTL I am using Magnetic Encoder ME6012 { Data sheet available @ ( http://www.google.co.in/url?sa=t&rct..._DNsH1LkQBYTZQ ) }

    Now can I use it with your circuit. I am new to the electronics

    Last edited by aadityadengle; 02-05-2012 at 04:25 AM. Reason: Additional Info


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    tried to connect with Magnetic Encoder but no use

    DATA == Cha A
    Clk == /A



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    Quote Originally Posted by aadityadengle View Post
    Yes!!!! Phase A & B with TTL I am using Magnetic Encoder ME6012 { Data sheet available @ ( http://www.google.co.in/url?sa=t&rct..._DNsH1LkQBYTZQ ) }

    Now can I use it with your circuit. I am new to the electronics
    No Sorry

    My PIC code works only with the 'chinese' LCD callipers (these output a binary code).

    Your scale needs a 'quadrature' counter - you may be able to find some other software to work with the scale (I believe the linux based EMC2 can do this)

    Bill

    Bill


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    tried the circuit with verniers too
    but no data

    Last edited by aadityadengle; 02-07-2012 at 01:56 PM.


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    Quote Originally Posted by aadityadengle View Post
    tried the circuit with verniers too
    but no data
    like that's going to get you an answer !

    Bill


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