Re: [CAD_CAM_EDM_DRO] Caliper to PC interface, Part II: Data Format ?????? Help ?

The fact that the same display value is outputting different values is a
problem hard to understand. It may be that the caliper has some logic to
average the data to remove the hysterics.
I agree with your theory that there are two sets or readings, relative and
absolute.
The closest I came with the data available was that that there are two 10
bit counters starting at offset 3 and 13 with the first counter the integer
and the second the fraction. Each count could be .0005 which may be the
resolution of the device. So the counters may be:

.000 - 00..0000
.0005 - 00..0001
.001 - 00..0010
.0015 - 00..0011
.002 - 00..0100

The negative does appear to be a 2's compliment of the counters.
The theory seems breaks down at higher values though so the 10 bit counters
may be several fields of data.
The first bit could be parity as most readings seem to have an odd numbers
of bits.

An interesting problem.

Graham

----- Original Message -----
From: "krlux" <lux@ca..>
To: <CAD_CAM_EDM_DRO@ya..>
Sent: Thursday, October 18, 2001 9:00 PM
Subject: Re: [CAD_CAM_EDM_DRO] Caliper to PC interface, Part II: Data Format
?????? Help ?


> Here is more data.
>
> The sign extension on the negative numbers is a good indicator that the
> format is a two's compliment.
>
> Someguy
>
> 0.001:
>
> 00 0000000000 0000000010 111010000000001110100101101 49d
> 10 0000000000 0000000010 110010000000001110100101110 49d
> 10 0000000000 0000000010 110010000000001110100101110 49d
> 10 0000000000 0000000011 000010000000001110100101100 49d
> 10 0000000000 0000000010 110010000000001110100101110 49d
>
> 0.000:
>
> 00 0000000000 0000000000 011010000000001110101000001 49d
> 00 0000000000 0000000000 101010000000001110100111111 49d
> 10 0000000000 0000000000 010010000000001110101000010 49d
> 00 0000000000 0000000000 011010000000001110101000001 49d
> 10 0000000000 0000000000 110010000000001110100111110 49d
>
>
> 0.0005:
>
> 00 0000000000 0000000010 001010000000001110100110011 49d
> 00 0000000000 0000000001 111010000000001110100110101 49d
> 10 0000000000 0000000010 000010000000001110100110100 49d
> 00 0000000000 0000000001 111010000000001110100110101 49d
> 00 0000000000 0000000001 111010000000001110100110101 49d
>
> 0.0015:
>
> 00 0000000000 0000000100 001010000000001110100100011 49d
> 10 0000000000 0000000100 010010000000001110100100010 49d
> 10 0000000000 0000000100 000010000000001110100100100 49d
> 10 0000000000 0000000011 110010000000001110100100110 49d
> 10 0000000000 0000000100 000010000000001110100100100 49d
> 00 0000000000 0000000100 011010000000001110100100001 49d
>