The IEC61850 MMS server technical key setting corresponds to the IEC61850 IED name.
This name is used to identify the device via a IEC61850 MMS client.
The size is restricted to 32 characters. According to IEC61850-7-2 Ed. the TechnicalKey represents
an IEC61850 VisibleString. Thus the following characters are allowed:
VisibleString ( FROM
('A'|'a'|'B'|'b'|'C'|'c'|'D'|'d'|'E'|'e'|'F'|'f'|
'G'|'g'|'H'|'h'|'I'|'i'|'J'|'j'|'K'|'k'|'L'|'l'|
'M'|'m'|'N'|'n'|'O'|'o'|'P'|'p'|'Q'|'q'|'R'|'r'|
'S'|'s'|'T'|'t'|'U'|'u'|'V'|'v'|'W'|'w'|'X'|'x'|
'Y'|'y'|'Z'|'z'|'_'|'0'|'1'|'2'|'3'|'4'|'5'|'6'|
'7'|'8'|'9') )