How to set unit properties for arrays in simulink?

I have 3x1 positionArray such as [latitude, longitude, altitude] and units are [rad,rad,m].

This array is in the input for simulink. Is there any way to define different units for array in simulink?

In the "Signal Attributes" section, i tried:

rad, rad, m

rad_rad_m

[rad,rad,m]

{rad,rad,m}

nothing works.

Unit specifications are explained in following link, but there is no information about array units.

https://www.mathworks.com/help/simulink/ug/units-in-simulink.html

[Chuguang Pan]

The three element in your 3x1 signal should have same unit. You can split positionArray into three seperate inputs and set units respectively.

[Kraker]

Inputs are kinda fixed. I am looking for the way to define different unit for array. It seems like not possible.

Answer 1

[Sreeram]

Hi Kraker,

Simulink does not currently support assigning different units for individual elements of an array directly. Units in Simulink are applied at the signal level, which means the same unit applies to the entire array.

A possible workaround is to create a custom "Bus" object. A Simulink Bus allows defining multiple elements with individual names, data types, and units. Here is how you can define it programmatically:

elems(1) = Simulink.BusElement;
elems(1).Name = 'Latitude';
elems(1).Unit = 'rad';

elems(2) = Simulink.BusElement;
elems(2).Name = 'Longitude';
elems(2).Unit = 'rad';

elems(3) = Simulink.BusElement;
elems(3).Name = 'Altitude';
elems(3).Unit = 'm';

positionBus = Simulink.Bus;
positionBus.Elements = elems;

For more information on "Bus" objects, the following documentation might help:

https://www.mathworks.com/help/simulink/slref/simulink.bus.html

I hope this helps!