X10 Meter design advice needed

["Robert Green" <robert_green1963@xxxxxxxxx>]

Hi,

I am currently testing and reviewing Jeff Volp's latest design effort, the
XTBM-Pro signal analyzer for X10 installations.

http://jvde.us/xtb/XTBM-Pro_instructions.pdf

We differ strongly on how the bargraph mode should operate.  The Pro's
bargraph mode is similar to how the discontinued ELK - ESM1 meter behaves
with one difference.  The last reading persists in the meter window.  The
ESM1 and other bargraph devices I am familiar with for measuring transient
signal levels all revert to zero when the signal stops so this strikes me as
a major exception to established display principles.

I realize that bargraphs that indicate state - fuel gauges, battery charge
indicators, copier tray capacity indicators and the like all persist. But
indicating a state of capacity is very different from indicating something
that occurs briefly, like a sound level or an X10 transmission, and then is
gone.

My opinion is that users will be confused by a bargraph that doesn't return
to zero after the signal has "passed."  To complicate matters, to keep costs
low, there's no scale on the bargraph readout as there is on the ESM1, so
all you see are two lines that say:

X: [][][][][]
N: [][]

There's no reference to voltage or the fact that the X: scale runs from 0 to
10 volts and the N: scale from 0 to 1 volt.  I've suggested changing the
display to display actual voltage levels:

X: [][][][][]     4.5V
N: [][]            0.1V

And I've also suggested that the low end of the scale be made more
sensitive.  My assumption is that if you've got a signal above 5V, you're in
the money and don't really need to know how much stronger than 5V the signal
is.  Sort of like the old joke about actors: "If you can afford to go to
Betty Ford, you don't really have a drug problem." (Your habit hasn't
consumed all your money - yet.)

The meter is perfectly capable of reading those high levels in the
alpha-numeric mode, but the bargraph mode is for quick and dirty signal
level checks.  That's why I think it should be extra sensitive in the low
range:  That's where people have the most X10 problems.

Other than this small design disagreement, the meter is smartly designed and
executed and has some features that are remarkable.  Using 2 way modules
like the RR501, Jeff's new Pro meter can test the voltage levels of all the
two way modules in your system and report them back to a control program
like HomeVision or even to the meter itself using dim levels to communicate
the remote voltage.

In addition, he's design the most useful bitmap mode I've seen, putting even
the venerable Monterey Powerline Signal Analyzer to shame.  Lynx had a meter
that attempted to do what Jeff's unit does, but you needed an attached PC to
use it.  (-:

And wait, there's still more!  He's built in a repeater check so that if you
have one installed, each time you plug in the meter, it measures the signal
strength of the repeated signal to the outlet being tested.  Unlike the much
more expensive Monterey, the XTBM-Pro's LCD is backlit, a boon for these old
eyes.

Feedback on whether the bargraph should persist or reset to zero after an
X10 command is received would be appreciated.  If you know of a bargraph
device that measures signals like X10 transmissions and "holds" that
reading, I'd like to know that.  My contention is that meters are designed
with HOLD buttons for similar situations and that holding the reading is the
exception, not the normal state of affairs.

--
Bobby G.