Question { Jindal, 8239 }

why pneumatic control signal output is use 0.2 to 1 kg/cm2

Answer

This is a standard which ws derived when pneumatic
instruments were in world being a good relationship was
observed in a range of 0.2 to 1.0 Kg/cm2. however, large
size high pressure final control element cannot operate
with such a low pneumatic pressure and it leads to
discovery of pneumatic positioners