Re: Cheap DRO system using digital scales and a PC

Hello,

i try to connect my digital scale with the computer. My digital scale
looks like that of http://www.guanglu.com.cn/Digital%20Height%20Gage%
20&%20Scale%20Unit.htm.
I have gotten following description to my digital scale:

Working of the interface: synchronus serial
Data: Binary code, 24 bits, each datum will send twice
The cycle is 300 ms (or 20 ms in fast reading state)
transmitting time 0,5 ms
Pulse range of data: Datum level <=0,2 V , level "1" >= 1,3 V
Clock pulse: CP 90 kHz, effective for high power level
wires: negative power, clock pulse, data, positive power.

To be read the data over the serial interface, it is very difficult
since the data-transfer takes place synchronized.
I want to try to read the data over the parallel interface.

Another problem is that the signal is very high-ohm-y (correct
english??). I tried the aticle of Lee
http://www.users.qwest.net/~indigo_red/files/calip /, thank you, but
my digital scale has negative impulses.
I exchanged the npn transistor with a pnp transitor and I got
positive impulses. Now I want to try as next to decode the signals
via parallel interface and visual basic...

Under http://www.guanglu.com.cn/Vernier%20Series.htm you can see a
plug.


Wilfried

http://members.xoom.com/rchobby/fraese/start2.htm