Understanding X10 Dims???
Using a CM11A to monitor dims (brights) on the power line, I notice that most X10 transmitters, e.g., CM11A, Mini/Maxi-controllers, RR501, send dims (brights) according to the formula: dims = 11*N + X where N >= 0 and X varies randomly - usually 2 or 3, sometimes 4. The CM11A reports a maximum of 210 dims.
The variation in X does not appear to be an imprecision in the monitoring interface circuitry - two CM11As on line simultaneously always report identical received values.
A strange thing about X is that a value of 3 or 4 produces _less_ actual dimming than 2. The effect is difficult to see with a standard X10 lamp module (and digital RMS multimeter) because of short term fluctuations in line voltage, but is very dramatic with X10's LM14A 2-way lamp module. With the LM14A, a plot of either extended level (0-63) or output voltage versus received dims (2-210 dims from the fully ON state) looks like a sawtooth curve with "tooth height" of as many as 6 extended levels or almost 10 percent. (There's a similar sawtooth curve from the fully OFF state when brights are received.)
Can any of the X10 hardware/firmware gurus on this newsgroup explain the reason for the variability of X in the transmitted dims and the strange retro effect of X = 3,4 versus X = 2 on X10 modules? Thanks for your help.
Regards, Charles Sullivan
read more and respond »Posted 5 years ago by Charles Sullivan in General Home Automation
