Patent ID: 11946740
Assignee: ELCOMETER LIMITED
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 15:
16. A method as claimed in claim 6 wherein the transfer function is, T
          ⁡
          
            (
            x
            )
          
        
        =
        
          
            (
            
              
                1
                
                  G
                  ⁢
                  1
                  ⁢
                  G
                  ⁢
                  2
                
              
              ·
              
                
                  
                    V
                    d
                  
                  ⁡
                  
                    (
                    x
                    )
                  
                
                
                  V
                  
                    o
                    ⁢
                    s
                    ⁢
                    c
                  
                
              
            
            )
          
          
            (
            
              1
              +
              
                
                  β
                  
                    G
                    ⁢
                    1
                    ⁢
                    G
                    ⁢
                    2
                  
                
                ·
                
                  
                    
                      V
                      d
                    
                    ⁡
                    
                      (
                      x
                      )
                    
                  
                  
                    V
                    
                      o
                      ⁢
                      s
                      ⁢
                      c
                    
                  
                
              
            
            )
          
        
      
    
    
      
        
      
    
  

where T(x) is the transfer function with output Vout(x)=T(x)Vin, Vd(x) is the detected output of the or each pick-up coil, Gi and G2 are the first and second scaling factors, and Vin, f3 and Vose are constants, Vin is a voltage set point used to control the alternating drive current, Vose is an amplitude of the alternating drive current and Vout(x) is the instrument output used to determine the measured coating thickness.