double Zmin = -150;
double Feedrate = 100;
double RetractHeight = 10;
double ProbeHeight = 2;                             // IMPORTANT: Change this value to your probe height

while(exec.IsMoving()) {}                           // Wait for any previous action to stop
exec.Wait(200);                                     // Wait for syncronisation

exec.Code("G31 Z" + Zmin + "F" + Feedrate);         // Start probing 
while(exec.IsMoving()) {}                           // Wait while there is motion 
exec.Wait(200);                                     // Wait for syncronisation

exec.ChangeaxisDROvalue(2, ProbeHeight.ToString()); // Change the Z DRO value to the probe height
exec.Wait(200);                                     // Wait for syncronisation

if(!exec.Ismacrostopped()) {                        // If the macro isn't interrupted...
    double Zretract = RetractHeight + ProbeHeight;  // Calculate a safe retract value
    exec.Code("G00 Z" + Zretract);                  // Retract the Z-axis 
    while(exec.IsMoving()) {}                       // Wait while there is motion
    exec.Wait(200);                                 // Wait for syncronisation
}