Some of you probably know I have been working on a new version of the simple plug-in XTBR. This version will not have the X10 Boost input on the cover, and will instead directly boost the strong signal from an X10 transmitter plugged into a nearby outlet on the same circuit. I’m in the process of testing that code now.
The old RR501 dim loop came up again. This time I had the storage scope monitoring the powerline signals so I could see what was going on.
When a dimmer button is kept pressed on a Maxi Controller, it will transmit a continuous series of those commands without any gaps between. A PalmPad working through the RR501 or TM751 works differently. When the PalmPad dimmer button is kept pressed, the RR501 sends packets of three half-doublets of that command, with about 260 milliseconds between each packet. In the “smart dim” mode, the XTBR or XTB-IIR will repeat the second and third half-doublets, which causes a full-step change in brightness. (A single half-doublet is a micro dim, which changes the brightness only about half a percent.)
When the smart dimmer mode in the XTBR or XTB-IIR is disabled, it responds to those commands like any normal commands by receiving the first half of the doublet, and repeating that in bit-sync with the second half. Because there is another half-doublet tacked onto the RR501 sequence, that is received and repeated in the gap following that third half-doublet. My guess is that is the reason for the 260mS gap.
If the repeated signal strength is in a certain range, the RR501 apparently gets stuck in a loop, sending the three half-doublet sequences continuously. That may be why some folks have reported that a single dim or bright command causes the lights to ramp to either off or full brightness.
It is interesting that moving the RR501 to a different location where it received a stronger repeated signal prevented it from becoming stuck in the loop.