The remote sense terminals should not be left open.
If you are not going to use the remote sense option, then you need to hook a wire between +V and +S. Also, hook a wire between -V and -S. This will put the power supply into what is referred to as “local sense”. The wire does not have to be a large gauge as there is very little current flow into the “sense” terminals.
In the diagram above think of the G540 as the “load”.