The variable Mass provides the weight of the load mounted on one mounting point.
The EngineeringUnits of the Mass shall be provided.
The variable CenterOfMass provides the position and orientation of the center of the mass related to the mounting point using a 3DFrameType. X, Y, Z define the position of the center of gravity relative to the mounting point coordinate system. A, B, C define the orientation of the principal axes of inertia relative to the mounting point coordinate system. Orientation A, B, C can be "0" for systems which do not need these values.
3DFrameType and 3DFrame are defined in OPC 1000111 (SpatialTypes).
If the instance of the LoadType describes the flange load of a motion device the mounting point coordinate system is the flange coordinate system. If the instance of the LoadType describes an additional load of an axis the mounting point coordinate system is vendor specific and it is up to the vendor to model this coordinate system.
The variable Inertia uses the 3DVektorType to describe the three values of the principal moments of inertia with respect to the mounting point coordinate system. If inertia values are provided for rotary axis the CenterOfMass shall be completely filled as well. Table 48 describes the possible degrees of modelling from a minimal one e.g. only the weight of the mass to a complete one comprising weight, center of mass, principal axes and inertia.
3DVectorType and 3DVector are defined in OPC 1000111 (SpatialTypes).
Table 48 – LoadType possible degrees of modelling

Mass 
CenterOfMass 
Inertia 

X, Y, Z 
A, B, C 


Mass only 
Used 
 
 
 
Mass with center of gravity 
Used 
Used 
0, 0, 0 
 
Mass with inertia 
Used 
Used 
Used 
Used 