5.2.22 - ReadDefaults (ReadCurrent) [U3 Datasheet]

I've not used the '5.1 General Protocol' before (just regular high level) and I am a bit confused about it. I'm trying to read in the Defaults using LJUD.eGet(LJ_handle, LJUD.IO.RAW_OUT, 0, dblByteCount, bytArray)  with the parameters in 5.2.22 

5.1 has extended command being bytes 0-5 with byte 2 being the number of data words.

Now 5.2.22 has 0-7 bytes associated with the command but byte 2 is only 1. Is this correct? Would it not need to be 2 to include the blocknum value?

I tried 1, and 2 but my returned values are always all zeros (no error). Am I missing or confused about something?

Georg

the command I am using is

LJerror = LJUD.eGet(ljhandle, LJUD.IO.RAW_IN, 0, dblByteCount, bytArray)

dblByteCount = 40 and bytArray is a 40 element array

my sending bytArray are: (248+1+14+128=391 = 1*256 + 135 which should have Check sum 1+135= 136)

136, 248, 1, 14, 0, 0, 0, 128, 0 (all remaining bytes are 0) (for block 0)   {88, F8, 1, E, 0, 0, 0, 80, 0}

137, 248, 1, 14, 0, 0, 0, 129, 0  (for block 1) {89, F8, 1, E, 0, 0, 0, 81, 0}

138, 248, 1, 14, 0, 0, 0, 130, 0 (for block 2) {8A, F8, 1, E, 0, 0, 0, 82, 0}

139, 248, 1, 14, 0, 0, 0, 131, 0 (for block 3) {8B, F8, 1, E, 0, 0, 0, 83, 0}

in all cases the bytArray after the call is unchanged and LJerror is [no error]

(even when I purposely mix up the values I still get LJerror of 0). I must be doing something fundamentaly wrong.

I can run a simple LJUD.eAIN( ...) command and retrieve a correct voltage

My U3 is hardware version 1.30 and I am running .NET 3.50 LJUD version

Working now, I thought checksum8 was bytes 1 to 8 (Table 5.1.2 says checksum8 includes bytes 1 to 15 but I missed the ?correction? somewhat below it where it says bytes 1 to 5 are what are used). I was also mistaken about checksum16, I started at 16 (which are zeros) because I thought checksum8 ended at 15 whereas checksum16 which actually starts with byte 6 .

For anyone else looking at this for block 0 of the defaults, my bytArray(40) is in size

bytArray={136,248,1,14,128,0,0,128} is the array sent, with dCount=8 in

LJerror = LJUD.ePut(LJhandle, LJUD.IO.RAW_OUT, 0, dCount, bytArray)

setting dCount=40, defaults for block 0 are received with

LJerror=LJUD.eGet(LJhandle, LJUD.IO.RAW_IN, 0, dCount, bytArray)

Thanks for the help LabJack.

Georg