possible to use a monitoring computer remotely and disconnect from it without closing the login screen?

possible to use a monitoring computer remotely and disconnect from it
without closing the login screen?

I have one Computer which is just running one application to monitor our
server data. This Computer will only be used for this purpose and I will
if there is a manageable possible solution unplug mouse and keyboard.
The monitoring tool is a web application so I just need to have firefox
opened.
When I now connect remotely with Remote desktop control I can open the
tool, but as soon as I connect I see the login screen on the monitoring
screen...( I use the same account as i use on my computer to connect AD
Account, tried another one, but it will log off the other user as well)
So what I need is to connect to that computer, start a tool and keep this
window open. If it's only possible with having any other plugin installed,
it's fine as well. If you miss any neccessary information, let me know.
EDIT : This is an additional monitoring system which does only run when i
am in the office, i start it in the morning and i shut it off in the
evening.