Time synchronization question for HiL-Application

[Lysandros]

Hello together,

this is my first post, so I am not sure whether I am in the right forum. I am planning to do a Hardware-in-the-Loop simulation. The Physics/System dynamics (modelled in Simulink on a host PC) will run on a real-time target, whereas the Hardware part, in this case a Brushless DC and a position sensor, will be real and connected to the target PC. Also, the target PC should send data in real time to the host PC for plotting and the host PC should send position commands to the target PC for adjusting the set point position.

I was advised to use the RS-485 network and I read through the specifications. But, I am not sure whether it will be fast enough for the the real-time requirements. Do I need special wires for this particular network? How can I make sure that the individual parts will be time-synchronized? Is the data been transfered point-by-point or in packages?

Thanks alot

[gregorelectric]

Hi, I am not sure if I understoo everthing right, but if you want to communicate in real time from your target to your host and back, then your host needs also to have real time functionality. Could you provide a more detailed description or a scheme picture of your system set up?

[Lysandros]

Thank you and sorry for the late response.

I have modelled a plant in state-space wich must run in real-time together with a test rig (for example at 1000Hz). For the model I am planning to use a target pc, like compactRIO. The test rig will provide the target pc with real sensor data and the target pc will generate the appropriate actuator signals. By the way, the controller structure is included in the model.

For the testing, there are several position and load sensors as well as two actuators. One actuator is to be tested (basicall the test module) and runs at 50Hz like it will be in the final application, while the other actuator is the load module, which represents virtual loads and thus also runs at 1000Hz. Both are controlled from the target output. The host computer is there only for parameter tuning, monitoring and data storage.

What would a suitable network configuration be for this setup? Is it possible or is necessary that the host and target run on the same clock? If I have two different rates, do they need to be synchronized?

Thanks alot