It is my understanding that you are not able to programmatically change the signal1 attributes of your Bus Element In block. You would like to know how you would be able to change the particular parameter (indicated in the attached screenshot) using your excel sheet.
A possible solution for the above question can be to use the set_param function to access and change the value of the parameter. You must specify the block object along with the signal in case of a Bus Element In block in order to change its parameter in the set_param function. The following example will illustrate on how to achieve the above:
% Assuming model name to be “Model1”
% Load the model in memory
load_system('Model1')
% Change the block parameter using set_param
set_param('Model1/InBus.signal1','Description','Your value')
% Save the model in memory
save_system('Model1')
Please refer to set_param documentation for more information on how to set Simulink parameter values.
