SAS WMS 550 black magic

[helg1978]

Hi!
I am trying to connect to WMS 550 by SAS, and I have something weird:
In no action state, machine send SAS adress and sometime 00 or FF bytes - can't unterstand why.
Some polls work fine - i can read meters for example.
But some polls  works incorrectly - for example poll  $54 = Send the SAS ID and machine serial number.
Answer is:
$54 = Message Length = 04
$54 = SAS version ID = 402
$54 = Serial Number  = 0ä¶

TX>= 07 54
RX<= 07 54 04 34 30 32 30 E4 B6

Real serial number much longer, so seems like error, but E4 B6 is the right checksum!!

Then, some polls have no response or zero response

I haven't SAS 4.02 manual (have sas 6.02) but sure can not be so big differenses in protocol!
So i am confused.  I've changed board - but same sh*t
Can somebody help?