nice find, heidenhain scales!

[Nicholas]

I spent most of the day at a local auction rooms, where I had my eye on some boxes of car parts, but during the veiwing i noticed there was a set of 2 heidenhain LS406C sealed scales (encoders), which was a real bonus cause i only paid $150AU. Anyway my question is does any body have the data on these babies?, I couldn't see them on the heidenhain site, but thats not to say there not there! Can i build the readout for them and mount them on my mill drill in the garage? or am i compelled to buy the heidenhain readout?
I might do some more research to see whats involved here. [img]/ubb/images/graemlins/cool.gif"%20alt="[/img]

Can't think of a good motto.

[Vampyr]

Short answer. Yup. And realistically there isn't much to it. Any electronics experience?

[Nicholas]

Yes, a little experience, but then I've had a bit of experience with auctions but still seem to come home with a lot of stuff that is pretty useless to any body that would have a life.
I'm keen to do this because i think i could learn from it (the readout). Thanks

[Vampyr]

There are about three ways off the top of my head...

#1 Use a... I believe it's called a mouse decoder. Your computer mouse basically uses the exact same thing, each axis has two square waves off set by 90 degrees, what order the pulses run tell it how far it has moved and in which direction, then you figure what kind of logic you need and display drivers....

#2 Use a PLD... Basically the same thing as above, but you stuff all the logic in a single chip. this really reduces the size of your control board. I like the Altera Max parts because they are very easy to program at home with a very easy to build programming cable (do a search on "build your own byteblaster"), and the FREE Altera development software makes setting them up extremely easy. (Basically you can draw it just like a schematic, and it compiles it into a downloadable program). I also have the AHDL routine for decoding mice around here to save you some figuring. AHDL is the text type logic programming. not as simple as laying gates and hooking them together, but much easier when doing if-then-else type statements or statemachines...
#3 write a program for a uP like any of the 80C51 series clones or about any PIC chip.
Once you work down to counting steps and detecting direction, it's just a matter of doing the math to figure number of steps to the inch and displaying it. If you want LEDs there are a pile of 7 segment display drivers available.

[Nicholas]

I am at this moment reading a book on the PIC micros, what would be the criterea for my choice of chip? (like maybe speed, don't think memory would matter). I guess the mid range devices would prpobably handle it ok (16f***).

Oh, and is a PLD the same as a PLC ?

I've got some nice DC motors laying around here, so I probably wont be happy with just the readout. but i guess the "walk before you run" thing applies here.

[Vampyr]

It's a very short walk from DRO to controller if you're into DIY. Part of the choice of controller is what you're comfortable with. 16F series is very potent, but you need to program in MPASM unless you're willing to buy a C compiler. Being the cheapskate that I am, I'd look at the 18F series since microchip is making an integrated C compiler for it. (also I'm a bit more comfortable in C) The 18 series are alot more expensive than the 16 series. Seems to me you might have to pay about $10.00.... Using an 18 series is like using a 2.4 GHz computer with 512M of ram and an 80 G harddrive to run a cash register...
Your processor will have to scan the inputs at 4 times the maximum frequency of the pulse train to decode properly. Make sure you don't over run your scan rate.

PLCs are kindof a generic term for programable logic controller. Some are much more potent than a mere PLD, sometimes the terms are interchangeable... A PLD is a programmable logic device. it is a single chip, where as some PLCs are little single board computers with a pile of support components...

I was just looking at a Rohm mouse encoder... The outputs are serial data and serial clock. (well the clock should be an input??) this implies that a pic with a syncronous serial interface would be a help. You may also want to look at the National LM628 and Agilent hctl 1100 series motion control chips before you pick your PIC. There are also some wonderful display/keypad controllers available for the I2C bus. That is a very useful interface to make a nice modular system that can grow with you.
Oh, one other thing, you may want to consider something that you can set up an RS-232 port on so that you can actually talk to your computer...

Here's a link to the decoders and motion control chips...
http://www.semiconductor.agilent.com


Alright... cropped because it didn't work....

[len]

I went to the Altera web site to check out their "free" software. Unfortunately, the software has so many strings attached to it that I lost interest. When I have to spend a half hour to figure out what "free" means to Altera, and play games with their licence files, I lose interest. Am I missing something? Why do you need a license file if it's free?

[Vampyr]

Erf. I'd swear I replied to this yesterday... I guess I'm used to getting a new license file every 6 months or so. The license file deal is really for access to the Mega Functions for their paying customers. Yes the liscense stuff is a pain in the rear, but it is worth it. I have NEVER come across an IDE that was that easy to use.

[Nicholas]

I think I'm slowly sinking in a paper printout swamp which used to be my study.
This programming thing can be pretty overwelming to a newy like me.

I'm thinking the modular system you mentioned earlier is the way to go, having the expansion capability would be very useful later, when i work out what "<<" & "&&" means.

I would have thought it would be a huge step from the DRO to full programmable CNC type.

How could i work out the speed of the pulse input from the scales? I don't have the specs here.

[dodimeister]

This post is great. First of all, let me just say that you guys need to pursue the linux avenue. C compilers cost money but the linux GCC compiler can be had for free and reconfigured for target process use. I have even seen it used to compile code for a 6809 processor... now there is a blast from the past! I have recently recompiled the GCC compiler for code development using the ARM 9 processor. Support for something like the MC 68HC11 is available as is support for the variety of pentium and intell chips. Siemens makes a display chip called a microdot. Comes in a variety of sizes but it can latch in the ASCII letter code and display it. No more decoding of 7 segment display. You write the ASCII letter code out to a specific address and bada-boom, its live! I am also using the altera parts and find them rather nice at least from a for profit point of view. I have considered using the smaller Excaliber chip for my home shop machinist stuff. It has an ARM 9 processor which can run up to 200 MHZ and FPGA space for logic. It uses the byte blaster technology. Also free on the list is ICRARUS VERILOG. Verilog is the logic lang used to design hardware. In the past, these tools were EXTREMELY expensive. Now, you can download the source code and images for icrasus verilog from the icrarus verilog site.

But verilog assumes you need to program logic support chips. If you can keep the speed down to say less than 10 or 20 MHZ, you can wire wrap discrete components with no difficulty. I used to buy electronic hobby stuff from JDR microdevices and they had a variety of niffy toys and parts.

Once you get comfortable with the notion of embedded C programming, its not a bad leap to using PC mother boards as embedded computers. You can loose the horrid BIOS routines and trash the microsoft virus. Load up the linux embedded OS and write code to your hearts content.

Buy a heavy duty hoffman nema 4 box and mount the mother board and power suppy. Now you can machine holes in the cover to take the good stuff such as a color LCD display (see JDR microdevices) or holes to accept stuff like allen bradley lights and switches snarfed from ebay and such.

Your going to need a G code and M code interpreter to run full CNC. Not a problem. Using linux as your embedded host, you just need to load up the latest version of EMC which is the gnu version of a CNC control package. Download this from the NIST sites for a wallet spiltting fee of nada... zippo.. .FREEEEBEEEE.

As for the switches, levers and other niffy add ons, you can control these fairly quickly by hooking them up on a breakout board or using a PIC control chip which intel makes. Then write a quick device driver according to the linux device driver book which is published by the O'Rielly nutshell folks. Same thing applies to any display enchancements you may have in mind.

Your imagination is your only limit on this stuff. Linux, GNU and GCC, etc. has taken a huge bite out of the number of dead presidents (mula, dinero, greenbacks) needed to accomplish this misson or objective. Lastly, this type of tinker work is a blast and more fun than a barrel full of monkies. You will love it.

Good Luck
Dev Emch