Diagrams User Guide
Diagrams : Piping & Instrumentation Diagrams (P&IDs) : Instrumentation : Instrument Relationship Shape
Instrument Relationship Shape
Instrument Relationship Shape does not represent a database element, but do represent a SCIREF between SCOINS and SCACTU. In the figure below, the dashed line represents a SCIREF from the SCOINS element at CCH-0 to the SCACTU representing the actuator at AT-12. The actuator has a SCIREF set to A150/Vv-002.
When Instrument Relationship Shape connects two valid items, it changes colour to ‘defined’. The colour can be determined in Diagrams Options:
As mentioned earlier, Instrument Relationship Shape does not represent any database element but it can display information from a database element that is associated with its start. It has a little support for SCIRTY because it is representing a connection. This connection type can be set using the Shape Data window. If the Text property is filled in, the Instrument Relationship Shape displays connection type value on drawing using SCIRTY attribute without index. The system will automatically find the correct one.
In the figure below the offline instrument has SCIREF set to equipment and actuator. A connection between the equipment and offline instrument is achieved by the control handle which is using an infra red interface. A connection between the offline instrument and actuator is achieved by instrument relationship line which is using an electrical interface.
Figure 5:14.
Offline instrument is controlling a valve via actuator
It is possible to use a relationship shape to connect an Offline instrument or Actuator to any valid item. The connection point will be created automatically on the shape if connection is at all possible, therefore it is not necessary to create any additional points on a shape that should be connected, before using the shape.
Note:
Note that connection points that are designed for process lines cannot be used to connect to a relationship shape. For example, a two way valve has two connection points that should be connected to a process line. If a relationship shape is connected to one of them, Diagrams will automatically disconnect it and present a message in the message log.
The direction of the relationship shape is not important. You can connect an Offline Instrument to a Valve or a Valve to an Offline Instrument:
The result in the Database will be the same. The only one exception is connections between Offline instruments and Actuators. Because both elements have SCIREF attributes, the system will set SCIREF on the element that has the connected relationship shape starting part. In the below example Offline instrument A will point to Offline instrument B. (SCIREF of Offline instrument will refer to Offline instrument B)
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