The calibrate the control valve used for mA Source 
Meter .mA Souce apply for I/P Converter so Opening Closed 
for Control Valve .At the opening closed time measured for 
position note.Supposed opening for Valve positioner 50% ma 
13.5 So adjust the Zero or Span Calibration to Control the 
ositioner  
Chart 
%   Actual Value     Error  Zero/Span                       
0         4.7mA       0.7     4mA                           
25        8.5mA       0.5     8mA                       
50        12.0mA      0.0    12mA                           
75        16.4mA      0.4    16mA
100       20.5mA      0.5    20mA