Fixes append_and_save issue

ohmpi/ohmpi.py

@@ -196,7 +196,7 @@ class OhmPi(object):
                 mm = np.repeat(last_measurement['M'], dd.shape[0])
                 nn = np.repeat(last_measurement['N'], dd.shape[0])
                 fwdata = np.c_[aa, bb, mm, nn, dd]
-                np.savetxt(f, fwdata, fmt=['%d', '%d', '%d', '%d', '%d', '%d', '%d', '%.3f', '%.3f'])
+                np.savetxt(f, fwdata, fmt=['%d', '%d', '%d', '%d', '%.3f', '%.3f', '%.3f'])
 
         if fw_in_csv:
             d = last_measurement['full_waveform']