diff --git a/meter_multical21.cc b/meter_multical21.cc
index 64bd2a6..81e3059 100644
--- a/meter_multical21.cc
+++ b/meter_multical21.cc
@@ -441,7 +441,7 @@ void MeterMultical21::printMeterFields(FILE *output, char separator)
 	    totalWaterConsumption(), separator,
 	    targetWaterConsumption(), separator,
 	    statusHumanReadable().c_str(), separator,
-            datetimeOfUpdateHumanReadable().c_str());
+            datetimeOfUpdateRobot().c_str());
 }
 
 #define Q(x,y) "\""#x"\":"#y","
diff --git a/meter_multical302.cc b/meter_multical302.cc
index be396e9..fdd57c1 100644
--- a/meter_multical302.cc
+++ b/meter_multical302.cc
@@ -199,7 +199,7 @@ void MeterMultical302::printMeterFields(FILE *output, char separator)
 	    totalPowerConsumption(), separator,
             totalVolume(), separator,
 	    currentPowerConsumption(), separator,
-	    datetimeOfUpdateHumanReadable().c_str());
+	    datetimeOfUpdateRobot().c_str());
 }
 
 #define Q(x,y) "\""#x"\":"#y","