From GridLAB-D Wiki
Character strings of 32 characters or less are stored in a char32 built-in data type.
An attempt to store a string longer than the maximum number of characters permitted results in truncation of the string to a length that fits.
GLM
To declare a char32 value in a class use the syntax
class my_class { char32 my_string; }
To define a string value in an object use the syntax
object my_class { my_string "value"; }
where "value" is a string of 32 or fewer characters..