diff --git a/src/channels.rs b/src/channels.rs
index 1a9bb7d..a2f3d55 100644
--- a/src/channels.rs
+++ b/src/channels.rs
@@ -265,7 +265,9 @@ impl Channels {
         let samples = 50;
         let mut target_voltage = ElectricPotential::new::<volt>(0.0);
         for _ in 0..samples {
-            target_voltage = target_voltage + self.read_vref(channel);
+            let vref = self.read_vref(channel);
+            self.channel_state(channel).vref = vref;
+            target_voltage = target_voltage + vref;
         }
         target_voltage = target_voltage / samples as f64;
         let mut start_value = 1;
@@ -372,7 +374,9 @@ impl Channels {
 
     // Get current passing through TEC
     pub fn get_tec_i(&mut self, channel: usize) -> ElectricCurrent {
-        (self.read_itec(channel) - self.read_vref(channel)) / ElectricalResistance::new::<ohm>(0.4)
+        let vref = self.read_vref(channel);
+        self.channel_state(channel).vref = vref;
+        (self.read_itec(channel) - vref) / ElectricalResistance::new::<ohm>(0.4)
     }
 
     // Get voltage across TEC