To specify a Parameter Database element, four integer numbers must be provided: a Database Item ID, a structure (i.e. group) index, a sub-structure index, and an array index.
The Database ID uniquely defines the type of information being accessed, e.g. a position loop feedback constant, the digital output channel that signals when the robot has reached its destination, the baud rate of the primary RS232 line, etc.
The structure index specifies a specific unit if there are multiple units in the system to which the Database ID applies. For example, when referring to a parameter that applies to the robot, the specific robot number (1 to N) must be defined with this parameter. For Database ID’s that refer to items for which there is only one unit possible (e.g. parameters for the controller), the structure parameter can be specified as 0 or 1.
The sub-structure index further qualifies the Database ID by defining a specific sub-unit of the unit specified by the structure index. Sub-structures are unusual, so this parameter is normally specified as 0.
Finally, the array index defines if a specific array element of a database element is being accessed. For example, when reading a servo tuning parameter for a given robot, there is typically one value per motor. For this database element, the array index specifies which motor is being referenced. If the database element only has a single value or if you wish to access all elements of the ID, a value of 0 can be specified for the array index.
The following are a few examples of the some Parameter Database specifications:
109, 0, 0, 0 -> Name of the controller
2708, 2, 0, 0 -> Default speed for robot 2
16077, 1, 0, 2 -> Maximum joint soft stop limit for robot 1, joint 2
16077, 1, 0, 0 -> Maximum joint soft stop limit for robot 1, all joints
If you primarily utilize the web interface to access the Parameter Database, much of the burden of the detailed ID specification is handled automatically.