pressure reduction valve positioning

[gtsolid]

Bye to all,
on a plant I have a valve and a pressure regulator, I would like to ask 2 things:
What's the difference between downstream or upstream piloting?
- Should the regulator be between the line and the valve or downstream of the valve?

 

[PIETRO2002]

I do not have a unique answer, I have seen both solutions, if for example you want to protect a cylinder against load increases, put the pressure regulator valve between the cylinder and the 3 or 5-way valve, so that, if during the race, the cylinder finds an obstacle, the pressure inside the cylinder increases and the regulator valve discharges the excess pressure safeguarding the mechanics or the particulars concerned.

 

[gtsolid]

What about the pilot?