Virtual Wiring Harness Overview

Earlier, under Architectural Concepts we introduced the idea of a Virtual Wiring Harness.  Here we explain how it is used in the context of the MxVDev test environment.

The Harness provides the set of Signals that are available to the tester in MxVDev.  This set of Signals is the Signals that pass between MxVDev and the SUT. Signals defined in MxVDev should have a corresponding port in the Harness.  At the early stages of a project, you may enter Signals directly into the Signal Dictionary. These Signals are only useful when they are connected to the Harness.

In the simplest case, these Signals match one-to-one with the I/O of the SUT (all of the Signal units and scaling match also).  In this case, the Virtual Wiring Harness is trivial, like a ribbon cable (wiring harness). A more complex Harness may include an interconnected web of Transforms. In this case, some Signals may be internal to MxTransit, and some Signals may be routed through intermediate Transforms between MxVDev and the SUT. In some cases the SUT may be a Transform.

Export Transform ports to connect the Transform to the Harness. (See Exporting Ports.) At this point, the ports become Signals in the Harness. It is not necessary to export all ports. Then, you can use the Connections dialog to add the Signals defined in MxTransit to the MxVDev Signal Dictionary. If necessary, the Connections dialog provides the capability to map MxTransit Signals to Signals already in the MxVDev Signal Dictionary. For simplicity, we recommend the names be the same, but it is not required.

The connection between the Harness and the SUT depends on the type of SUT:

In some cases, the Harness itself may be the SUT. The Getting Started with a C# Snippet project is a simple example of using a Transform in the Harness as the SUT.

For SIL testing with the MxVMC, the Harness is connected to a VMC. The VMC harnesses a software component (SWC) which is the SUT. The VMC harness is considered part of the Transform, not part of the Virtual Wiring Harness.

For MIL testing, the SUT is a Simulink model, and the Harness connects to it using an S-Function Connector Transform.

For HIL testing, the Harness connects to an external SUT using Connector Transforms.

If your SUT has a single VMC, you can also use Data Routing in the Signal Dictionary.

Related Topics:

MxTransIt Overview

Connecting Signals

Disconnect/Connect Harness

Exporting Ports