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[Brandt]

I noticed when dimming lamp modules with a palmpad travelling through the w800usb and out the CM11a and through an XTB-IIR takes forever!!! I then turned off that house code for the w800usb via heyu and used a TM751 instead and noticed that dimming is flawless and smooth.

Can anyone recommend how to remedy this so I don't have to use a (TM751 plugged into my XTB-IIR) for better dimming and can solely rely on the w800usb/XTB-IIR/CM11a combo?

[JeffVolp]

It sounds like you are seeing the difference between normal dims versus micro-dims.  In one case there are about 20 normal dim steps from full on to full off.  In the other case there are well over 100 micro-dim steps covering that range.

The actual dim commands are the same, and the difference depends on how they are formatted.  A dim command comprised of two identical halves is interpreted as a normal dim, but one half of a dim command with at least a 3 cycle gap before the next dim command is interpreted as a micro-dim.  That causes a problem for some repeaters which are not capable of repeating both halves of a normal dim command, changing them into micro-dims.  The XTB-IIR is capable of repeating both versions if the Smart Dim mode option is enabled (which it is by default).

For more information on the different dim commands, see Dave Houston's excellent document:

     http://davehouston.net/micro-dim.htm

Jeff

[Brandt]

So I wonder what is responsible in this case for changing it to micro-dims? Hardware? Software?

There is a dimming directive in Heyu:

TRANS_DIMLEVEL directive

This directive specifies the dim level (1-22) for each RF Dim or Bright signal transceived (or forwarded) by heyu_aux. The default level is 2 which results in a brightness level change of about 6 percent in standard X-10 Lamp Modules.
Example:

  TRANS_DIMLEVEL  2 

[JeffVolp]

It is not possible for any repeater to repeat the first half of a dim doublet because it must receive the first half before it knows it is a dim command.  The second half of the first doublet is repeated, as is every subsequent dim in the sequence.  It is not possible to glue the missing first half onto the end of the sequence because it will collide with any other command following the dim sequence.

If the CM11A sends the sequence of dim commands as individual doublets separated by gaps, a module that cannot see the direct transmission from the CM11A will interpret them as micro-dims.  The fix is to send the sequence without gaps, as does the Palmpad -> TM751.  Note that a module that cannot see the direct transmission will respond with one fewer dim step because the first dim is converted to a micro-dim.

The other option is to plug the CM11A into the XTB-IIR to take advantage of the direct X10 Boost mode.  In that mode the entire sequence, including the first doublet, will be transmitted at high power.

Jeff

[Brandt]

The other option is to plug the CM11A into the XTB-IIR to take advantage of the direct X10 Boost mode.  In that mode the entire sequence, including the first doublet, will be transmitted at high power.

Yep, I've been planning to do this. I just bought a handset cord coupler and some 4p4c plugs to crimp onto some telephone wire so that the cm11a will be able to reach the laundry room where my xtb-iir is! 

[Brandt]

ok I have the CM11a plugged into the XTB-IIR now, and the dimming is the same 

Flawless with a palm pad and TM751, and slow with the w800usb and cm11a plugged into an XTB-IIR

There is about 3 seconds between each dim step, but they are definitely not micro dims.

[JeffVolp]

With the CM11A plugged into the XTB-IIR, it is sending to the powerline exactly the same commands that are issued by the CM11A.

A micro dim is one half of a dim doublet, where a normal dim is a full doublet.  If the w800 -> CM11A is working differently than through a TM751, then somewhere the dim commands are being modified.  For rapid dimming, you need to send both halves of a dim doublet.

Jeff

[Brandt]

Thank you, I'll have to ask around on the Heyu mailing list.