diff --git a/libraries/AP_ADC/AP_ADC_ADS1115.cpp b/libraries/AP_ADC/AP_ADC_ADS1115.cpp
index d30bf996ac2ce..09ffbbcd340ec 100644
--- a/libraries/AP_ADC/AP_ADC_ADS1115.cpp
+++ b/libraries/AP_ADC/AP_ADC_ADS1115.cpp
@@ -135,6 +135,11 @@ bool AP_ADC_ADS1115::init()
 
     _gain = ADS1115_PGA_4P096;
 
+    // initialize the sample cache to ensure we know if it was populated with valid data
+    for (size_t i = 0; i < _channels_number; i++) {
+        _samples[i].data = -1.0f;
+    }
+
     _dev->register_periodic_callback(100000, FUNCTOR_BIND_MEMBER(&AP_ADC_ADS1115::_update, void));
 
     return true;
diff --git a/libraries/AP_DroneCAN/dsdl/rb/31000.ADC.uavcan b/libraries/AP_DroneCAN/dsdl/rb/31000.ADC.uavcan
new file mode 100644
index 0000000000000..4167ec89b42c5
--- /dev/null
+++ b/libraries/AP_DroneCAN/dsdl/rb/31000.ADC.uavcan
@@ -0,0 +1 @@
+float32[<=10] voltages
diff --git a/libraries/AP_DroneCAN/dsdl/rb/31000.uavcan b/libraries/AP_DroneCAN/dsdl/rb/31000.uavcan
deleted file mode 100644
index ea10a4decbf05..0000000000000
--- a/libraries/AP_DroneCAN/dsdl/rb/31000.uavcan
+++ /dev/null
@@ -1,6 +0,0 @@
-#
-# ADC voltages
-#
-
-float32[<=10] voltages            # [Volt]
-