3051l

i have rosemount transmitter 3051L and it installed at waste water tank but when i want to replace it by new one i can't as there is no isolation valve found so i installed manual valve before transmitter.is this action effect at measuring and gives error or there is no effect and this is the right action or you have another solution....

The potential error is any elevation shift (elevation added to or subtracted from) the elevation zero point (the datum, or reference point).

Obviously, a closed valve prevents pressure from reaching the sensing diaphragm, but an open valve should not affect the measurement other than the aforementioned elevation shift that a valve creates.

is there any standard said this speech?