diff --git a/datalogger/src/main/java/org/obd/graphs/bl/collector/CarMetric.kt b/datalogger/src/main/java/org/obd/graphs/bl/collector/CarMetric.kt
index ed3b0eb7..abb1aa79 100644
--- a/datalogger/src/main/java/org/obd/graphs/bl/collector/CarMetric.kt
+++ b/datalogger/src/main/java/org/obd/graphs/bl/collector/CarMetric.kt
@@ -7,14 +7,14 @@ import org.obd.metrics.pid.ValueType
 
 data class CarMetric(
     var source: ObdMetric,
-    var value: Number,
+    var value: Number?,
     var min: Double,
     var max: Double,
     var mean: Double,
     var enabled: Boolean = true
 ) {
     companion object {
-        fun newInstance(source: ObdMetric, value: Number = 0, min: Double = 0.0, max: Double = 0.0, mean: Double = 0.0)
+        fun newInstance(source: ObdMetric, value: Number, min: Double = 0.0, max: Double = 0.0, mean: Double = 0.0)
         = CarMetric(source, value = value, min = min, max = max, mean = mean, enabled = true)
     }
 
diff --git a/giulia_renderer/src/main/java/org/obd/graphs/renderer/DrawingManager.kt b/giulia_renderer/src/main/java/org/obd/graphs/renderer/DrawingManager.kt
index ab28da9b..3934c2a5 100644
--- a/giulia_renderer/src/main/java/org/obd/graphs/renderer/DrawingManager.kt
+++ b/giulia_renderer/src/main/java/org/obd/graphs/renderer/DrawingManager.kt
@@ -90,7 +90,7 @@ internal class DrawingManager(context: Context,  private val settings: ScreenSet
         paint.color = color
 
         val progress = valueScaler.scaleToNewRange(
-            it.value.toFloat(),
+            it.source.value?.toFloat()?:it.source.command.pid.min.toFloat(),
             it.source.command.pid.min.toFloat(),  it.source.command.pid.max.toFloat(), start, start + width - MARGIN_END
         )