When you look at the binary name encoding data for the PLC-5, you see the
following defination (paraphrased)

mask, level1, level2, level3, level4

mask is a simple bitwise mask that indicates which of the following levels
of data are present.  If the data is not present, then a default value
(usually 0) is assumed for that level.

For the following discussion, use the following as an example:
		Wx:yyy.zz

Level 1 indicates the area of the system you wish to read.  For the data
table, this is 0.  This byte must always be encoded.

Level 2 indicates the file number of the address.  This is the 'x' of the
example.  Note that the 'W' indicator is not dealt with at all.

Level 3 indicates the element number.  This is the 'yyy' section of the
example.

Level 4 indicates the subelement number.  This is strictly for such things
as seperating out the accumulator from the preset of a single timer.  As
near as I can tell, it does not work for reading an individual bit from the
PLC.  In other words, T4:0.acc is encodable, but N7:0/1 is not.

This is all well and good.  It allows us to read all of the data table of
the PLC without too much trouble.  Unfortunately, this addressing scheme is
also used for reading "system" areas of memory.  Things like the PLC2
compatibility file (does anyone still use this?), the ladder/files, etc. 
Within these other areas, they can all be addressed just like above, but the
meanings of the different levels are obviously different.  For example, I
have seen level 1's value go as high as 6.  

The bad part about all of this is that it is all undocumented, at least to
the commom person like me.

As I discover useful things about these other "sections" of memory, they
will be documented here.

------------------------------------------------------------------------------

Well, I have made quite a few little discoveries about the system levels...

The following annotation refers strictly to the SoftLogix 5 product as that
is all I have to test with.  As I discover things about the rest of the PLC5
line, as well as the Pyramid and the SLC5/05, they will also be documented
here.

The entire ladder program (including all files) is stored in System Area 1. 
The Input and Output Force Table is stored in System Area 2.
Area's 3,4,5 & 6 store such things as communications channel configs,
sidecar arrangements/data, and what not.  I have no idea currently as to
what is stored where.  The discovery of these things is currently not a high
priority.

