Availability:
     Level 5    , 'G'

  Quick Help:
     Select Servo Controller, G[Head],[Controller],[InputShift]

  Description:
    This command allows for one of serveral different servo controllers to be selected.
    The servo controllers available have been pre-designed with dynamic characteristics
    which have been optimized for particular operating conditions.

  Input Parameters:

    If no parameters are entered, then the command will display the 
current "controller"
    for all heads. Then the current "input shift" will be displayed.
    0 - Head
    
        This parameter specifies the head or heads to select the servo 
controller.
    
        If only parameter 0 is specified:
          The command will display the current "controller" selection 
for the specified head.
          Then the "input shift" will be displayed.
    
        If parameter 0 is specified,
        And either or both parameter 1 and parameter 2 are specified:
          The "controller" for the specified head is changed to the 
specified values and/or
          the "input shift" will be set to the specified value.
          Then the command will display the current "controller" for the
 specified head.
          Then the "input shift" will be displayed.
    
       If parameter 0 is NOT specified
       but either or both parameter 1 and parameter 2 are specified:
          All the current "controller" are changed to the specified 
values for all heads and/or
          the "input shift" will be changed to the specified value.
          The command will then display the current "controller" for all
 heads.
          Then the "input shift" will be displayed.
        
       Other combinations are invalid.
                                                                                                            
          Type:    Unsigned 8-bit value
    
          Range:   0 .. Max Head
    
          Default: None
    
    1 - Controller
    
        This parameter specifies the servo controller to be used.
    
          Type:    Unsigned 8-bit value
    
          Range:   Defined by Servo
    
          Default: None
    
    2 - Controller Input Shift
    
        This parameter specifies the Conroller Input Shift
    
          Type:    Unsigned 8-bit value
    
          Range:   Defined by Servo
    
          Default: None
    
  Output Data:


    If an error occurred, the following information will be displayed.
    
          "DiagError aaaaaaaa"
    
       where
    
          aaaaaaaa is the Diagnostic Error Code
    
    If no error occurred, the servo controller information will be displayed as follows.
    
          "Head Controller"
          "AA   BB"
            .
            .
            .
    
          "Input Shift: CC"
    
       where
    
          AA is the Head Number.
    
          BB is the Controller Number selected for the specified head.
    
          CC is the Input Shift value.
    
    Note: Controller Data will be either for a single head or for all heads depending on
    parameters selections when the diag is executed.
    
  Revision History:

    0001.0000   Initial revision.
    0011.0000   Combined the PSG Diagnostic Error Codes (PSGDEC) and the Diagnostic External
                Test Service Error Codes (DETSEC) into a single set of Diagnostic Error Codes
                (DiagError).