Does anyone knows what does the byte "30" at the end of a password byte array means?

Does anyone knows what does the byte "30" at the end of a password byte array means?

hi, i'm making a tool to write and read to the nais plc. FP0-C14.

the thing is, i can get it to connect from my program i coded with C#. (don't bother wat language i use for coding, not my question point.)

my problem is for example:

1. I locked my plc with the password call "1234" from FP WIN GR.
2. I manage to use my C# program to connect to the plc.
3. I try to write the password into the plc and get an error respond.
4. the fake password i wrote to try is "A1B2".
5. but when i look from the serial port monitor, it's "%EE#152B2A130"
6. I know that i shouldn't bother the 1st part, which is "%EE#152". Because it's always the same no mather what password i write into it.
7. I know the password will be swapped from left to right with the byte[].SO it will change from "A1B2" into "B2A1".
8. Here's my real problem. It added a "30" after the password. What does it mean? it is not static, it's range is wide, it increased and sometimes decreased.

the whole byte array will be writen to the plc is:
%EE#152 B2A1 30

So can anyone help me out?
I just need ot know what does the "30" in the end of that byte array means.

Thanks.

My guess:
End Byte marker or blank. The EE#152 is the Start Byte, but might not contain length info.
I remember an old program that reserved 128 bytes for the password. The blank fields were filled with '30'.

i know "EE#152" is the start bytes, but I dont think the end byte is a blank or reserved 128.

here's a few try outs.
Password "0000" = %EE#152000030
Password "FFFF" = %EE#152FFFF30
Password "1234" = %EE#152341234
Password "4567" = %EE#152674530
Password "6654" = %EE#152546631
Password "6655" = %EE#152556630
Password "6789" = %EE#152896730
Password "6788" = %EE#152886731
Password "6787" = %EE#15287673E

from what I am trying to know, it looks like it means something but i just couldn't get it.