Dragging Equipment and Piping Networks

If equipment is repositioned using ordinary positioning commands, the pipes connected to it do not automatically move with the item. The DRAG command is used to move Constrained Networks of Piping, Equipment and Nozzle elements all together. How the constrained network is created depends on the direction of the dragging operation and the type of item being dragged.

When a DRAG command is given, the current element is displayed normally, together with the constrained network. This network finishes where a legal end is found.

Items that can be dragged are:

• Piping Components

  In this case the network is formed by searching outwards in all directions from the component until a legal end is found for each ‘leg’ of the network.

• Nozzles

  The piping network connected to the Nozzle is searched for legal ends.

• Equipment

  The piping networks connected to all Nozzles owned by the equipment are searched for legal ends.

A legal end for a constrained network can be:

• A piece of tube that can be extended parallel to the displacement

• A piece of tube that can be compressed parallel to the displacement without becoming negative in length

• A Nozzle

• A point between two mis-aligned components

• A point between two incompatibly-connected components

• Any component that has not yet been positioned and orientated

• Any element in a design area that cannot be modified due to the designer’s access rights

In some instances, the DRAG operation may fail to establish a constrained network. This may be because:

• The internal search limit has been reached

• A LOCKED element has been found in the network