Multiple sonar simulation with gazebo

Hi,

For testing my code with multiple sonar I would like to run a gazebo simulation with multiple sonar sensors on my model.

However I can only find an example SDF file with a single sonar sensor. When copying this single sensor multiple times I get no readouts. When I then change the element name from sonar::link to for example sonar_1::link I will also not get a readout when only having a single sensor.

Any one here who can tell me what I do wrong or can give me an Example SDF file?

Best regards.