Using Pre-Set Dim

Questions

How do I use the old Pre-Set Dim command?

History

When the X10 protocol was originally developed it was realized that a method telling the module what brightness to change to would be desirable, so the Pre-Set Dim command was created, but for a variety of different reasons it wasn't implemented. Later when X10 developed the Extended X10 Code Protocol, they obsoleted the old Pre-Set Dim commands (they had never used them) and replaced them with new Extended Dim commands. Unfortunately some third party manufacturers were using the Pre-Set Dim command and some still do, so the old Pre-Set Dim command has never really gone away.

Answer

The old Pre-Set Dim works in a funny way in that the house code in the command is used to determine the On-Level. Since X10 never used the old Pre-Set Dim the levels were never standardized. The only hint on how it should be implemented was in the Powerline Carrier description it says, "In a Pre-Set Dim instruction, the D8 bit represents the Most Significant Bit of the level and H1, H2, H4 and H8 bits represent the Least Significant Bits." As a result each manufacturer decided what On-Level should map to each value.

SmartHome's Implmentation of Pre-Set Dim

Below you will find a chart describing how SmartHome implemented Pre-Set Dim in their modules. For convenience I have included the Fade rate that each on-level maps to when configuring the module (for more details on configuring the modules please refer to the documentation that came with your module). This chart may or maynot work for other brands of modules.

House Code	X10 Binary Code	Pre-Set Dim1			Pre-Set Dim2
		On- Level	Fade Rate	Adv Fade Rate	On- Level	Fade Rate	Adv Fade Rate
M	0000	0%	9.0	9:00.0	52%	0.5	0:34.0
N	1000	3%	8.5	8:00.0	55%		0:32.0
O	0100	6%		7:00.0	58%		0:30.0
P	1100	10%		6:00.0	61%		0:28.0
C	0010	13%	6.5	5:00.0	65%	0.3	0:26.0
D	1010	16%		4:30.0	68%		0:23.5
A	0110	19%		4:00.0	71%		0:21.5
B	1110	23%		3:30.0	74%		0:19.0
E	0001	26%	4.5	3:00.0	77%	0.2	0:08.5
F	1001	29%		2:30.0	81%		0:06.5
G	0101	32%		2:00.0	84%		0:04.5
H	1101	35%		1:30.0	87%		0:02.0
K	0011	39%	2.0	1:00.0	90%	0.1	0:00.5
L	1011	42%		0:47.0	94%		0:00.3
I	0111	45%		0:43.0	97%		0:00.2
J	1111	48%		0:38.5	100%		0:00.1

Related Articles

Powerline Carrier

Standard and Extended X10 Code Protocol

Phil Kingery's Which One Should I Use #18