Still have a problem... :(
Maybe you know DS18B20. I'm reading the 8 byte ID (64 bit code) of every
sensor used on the bus (one by one inserting it manually into the socket).
Then I'm inserting all sensors on the bus and reading the temperature of the
matched sensor. So far so good, everything works OK on a bus of 100m lenght.
Since I can use less than 9 sensors on the bus (from the 9 software
predefined), say only 3, I'm performing the ID match only for 3 sensors. If
I read the other 6 sensors left (which ID does not match) the value I got is
31.9 (in terms of celsius temperature).
With one sensor connected on the bus I've managed this by reading the sensor
presence bit. If there is no sensor on the bus, I display a message "OPEN".
However, with more than one sensor on the bus I never got this message,
because always there is at least one sensor on the bus, even with other ID
than expected.
I don't know yet how to solve this. I need to display somehow if there is
an empty socket to a corresponding sensor name. There is a too complex
algorithm for this operation called search ROM, which I don't want to use
it...
Example: s1: 22.5
s2: 37.5
s3: 60.0
s4: OPEN
s5: OPEN
s6: OPEN
etc
On Sun, May 16, 2010 at 4:09 AM, Joep Suijs <[email protected]> wrote:
> :) JAL & Sustainability!
>
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