_CheckTextLength

Characteristic	Description
Availability	Text items
Description	Checks whether the value entered in the item is less than the maximum length. The maximum length is 255 by default, but you can specify any value when you create a rule based on the template.
Returns	True—The value entered contains fewer than 255 characters. False—The value entered contains 255 characters or more.
Display text	this.Value.Length < MaxLength