Change the direction of a conveyor via input parameters

Hello,

for a Student-Project we designed a Model of a sorting plant. It's running and connected to SIMIT and TIAv14.

While running our simulation we noticed that our guideline wants the conveyor running backwards or forwards on a klick on the HMI-Panel.

We tried negative speed but as its an unsigned integer it just sets the maximum speed.

We have to change the vector direction of the conveyor but it this possible via input parameters?

I'm thankfull for every answer

Regards,

 Laura

PS: I hope I chose the right sub-forum