You can output the value at the specified coordinate by following steps.
The data will be output as a text file such as the followings in the postProcessing directory in the OpenFOAM case directory.
# Probe 0 (50 55 0) # Probe 0 # Time 1 (0.0147658 -4.4128 0.0005997) 2 (0.0234103 -6.16495 0.0140222) 3 (-0.0857817 -12.9339 0.0530903) 4 (-0.00578284 -14.2731 0.208692) 5 (-0.00674051 -13.8961 0.268186) 6 (-0.363481 -11.7431 0.0795817) 7 (-0.540394 -10.0883 -0.166615) 8 (-0.63744 -9.94229 -0.131043) 9 (-0.60769 -10.6763 -0.176582) 10 (-0.458593 -12.2571 -0.130862) 11 (-0.417252 -13.3228 -0.139157) ・・・(省略)・・・