Author Topic: XTBM and XTBM-Pro 0.00V Readings  (Read 1464 times)

Jeff

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XTBM and XTBM-Pro 0.00V Readings
« on: September 26, 2013, 08:13:42 AM »
Several customers have reported X10 commands being decoded with 0.00V signal levels.  This has been puzzling because I had never seen an X10 signal level that low in my testing.  I was able to recreate that today, and those readings appear to be valid.  Essentially, it means the signal level is below 10mVpp.
 
First I read the output from a Maxi controller directly, and then through an XPPF filter.  The levels were 6.64V and 0.16V respectively.  So that shows the filter is reducing the signal level by about 97%,
 
Then I read my test signal, which is on the other phase from my isolated lab test phase.  That read just 0.06V, which is the signal that I use to test the repeater function in all XTB-IIRs.  Then I read that signal through the XPPF, and the XTBM-Pro was still able to decode it with a 0.00V signal level.  If that 97% reduction holds up at that low level, the signal would have been only about 2mV.  I think it is safe to say that the signal would be below .01V, and hence the .00V reading.
 
I had never seen the XTBM or XTBM-Pro decode a signal that low because my powerline noise runs .01V to .02V.  Connecting the XTBM-Pro through a filter reduced both the noise and signal level, and showed what the XTBM can really do in a very low noise environment.

Jeff
X10 automation since the BSR days...

Jeff

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Re: XTBM and XTBM-Pro 0.00V Readings
« Reply #1 on: September 27, 2013, 11:00:58 AM »
I wanted to report a follow up on this issue.  The recent XTBM-Pro firmware update increases the resolution below .04V so it can display readings as low as .01V.  I don't have any X10 modules that will respond to signals that low, but the XTBM-Pro will detect signals that low in a very low noise environment.

Jeff
X10 automation since the BSR days...

 

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