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Radridz3
02-07-2010, 04:50 PM
I have a seig x-1 mini mill thats all mod'd out. 3axis cnc setup and 4th axis rotary table. Currently it is up and running with mach3 on db25, and a bs-2 runnin relays on db9. My mills in the garage and the com cables go threw wall plates to computer inside. Now instead of me just running some vga out in the garage . I wanted to put a cheap DIY Dro system on the mill (4 JOGGING PURPOSES) made with those cheap chinese digital caplipers. Which would be the scale. Theres 4 pins on it····· pos. neg. data. clock......I want these·4 scales to connect to a stamp. And before you say 2 use spin the answers no . I know absolutly
nothing about writing spin.
····· Any demo code or help or links or knowledge in general would be appreciated. And another question is I've seen these diy dro's using attiny's but the readout software runs on dos and im not going back that old school.· So in short (4 scales to BS-2 to 4x20 parlx display. I can write the code to display results on 4x20 and debug but have now idea how 2 write the scales interface part.

$WMc%
02-08-2010, 11:52 AM
Radridz3

A little info on Your scales:

With the calipers jaw to Your left and looking down on the unit. the pin out is as follows

Vneg-Data-Clock-Vpos

This scale does not use the Digimatic Protocol.

Instead it uses two 24 bit words @ ~ 90 kHz, LSB first, with a 55uSec POS start bit.This is followed buy the 24 bit packet. two 55uSec periods follow then the 2nd packet, 24 bits LSB.

Theres about a 300 mSec pause between data packets

The first packet is the absolute and the 2nd is the relative position.

With the use of a Module drop, The Stamp could read the scales. This is only because of the 300mSec delay between data packets.

Other wise the Stamp is not fast enough.

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The Truth is out there············___$WMc%___······················ ······ BoogerWoods, FL. USA

upand_at_them
02-08-2010, 11:59 PM
There are 3 data formats used in the Chinese digital calipers/scales. Do you have a oscilloscope to look at the pulses?

2x24: Transmits two 24-bit words. First word is the absolute position. Might sound useful, but the reference point is unknown and resets every time you remove power. Second word is the relative position, it's relative to your zero point.

BCD7: Transmits 7 nibbles (4 bits). Each nibble is a digit in BCD.

BIN6: This is what my calipers use (purchased from VXB). Transmits 24 bits. Bits 0-20 contain the number. The last nibble contains flags. When in inches mode you need to multiply the transmitted value by 5 (weird!).

Some helpful places with information:
1. Shumatech's website has info on the 2x24 protocol.
2. www.yadro.de has info on the 2x24 and the BCD7 protocols.
3. The Shumatech Yahoo group has info on the [new] BIN6 protocol in their files section.

Notes:
1. A regular Stamp is not going to be fast enough to decode the signals.
2. The first two protocols can be switched to fast output mode, which is going to be necessary if you want to move the mill axes at any reasonable speed. Data bits are read on clock falling edge.
3. BIN6 protocol doesn't have fast output mode, will power off when idle, and data bits are read on clock rising edge.
4. The Shumatech Yahoo group has PIC assembly code for interfacing with BIN6.
5. Shumatech's website might have their code, I dunno, I thought it was open source.

Right now I have a PIC16F88 hooked up to a caliper since my HomeWork Board stamp wasn't fast enough.

Mike

upand_at_them
02-09-2010, 12:52 AM
And another thing: the calipers output pulses that go from 0 to 1.5V, so you'll need a level shifter. I'm using an op-amp with a gain of 3 to give 0 to 4.5V. It works. The part was on my desk so I used it, but a voltage comparator is a better choice since it's faster and will produce sharper pulses.

Mike

Radridz3
02-09-2010, 11:51 AM
Thanks for the reply's Gentlemen . Yes on the scope . And Im scratchin this project just don't have time for just jog info.>.>>..