Encoding array

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By simba, 21 October, 2011

Can somebody explain me how to read array data type? For example I have array which I get reading all cosem objects and one small part in hex values, is showed bellow:

01 82 01 71 02 04 12 00 08 11 00 09 06 00 00 01 00 00 ff 02 02 01 09 02 03 . . .

So first byte "01" is for data type ( in this case array data type, according to blue book), but I don't know what means next 3 bytes. Can somebody help me? Thanks

Best regards,

Kurumi

14 years 6 months ago

Hi,

Following tree bytes tell amount of the items.

Accordin DLMS/COSEM spesification, if there are more than 127 items
amount is divided to multible bytes.

Example: Items count = {byte array according DLMS/COSEM}

2 = {0x2} //Higgest bit is not set. Data item count is two.
127 = {0x7F} //Higgest bit is not set. 127 items.
240 (0xF0) = {0x81, 0xF0} //Higgest bit is set. Data count takes one byte.
287 (0x11F) = {0x82, 0x01, 0x1f} //Higgest bit is set. Data count takes two bytes.

So higgest bit of the first byte is set if number of items is more than 127.
Lowest byte tells how many bytes takes to show the number.

Hope this helps. :-)

Happy coding,

Mikko

Dear kurumi,

Same encoding procedure applies to structure also (If structure contains more than 127 elements)?