### 7 OPC UA ObjectTypes

### 7.12 LoadType ObjectType Definition

## 7.12.3 ObjectType description

## 7.12.3.1 Variable Mass

The variable *Mass* provides the weight of the load mounted on one mounting point.

The *EngineeringUnits* of the *Mass* shall be provided.

## 7.12.3.2 Variable CenterOfMass

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 10001-11 (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.

## 7.12.3.3 Variable Inertia

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 10001-11 (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 |