feat(tempdeck-gen3): include thermal calibration offsets when calcula…

…ting temperature (#443) * Convert thermistor readings with thermal offset constants * Added tests that EEPROM constants change the temperature readings
Opentrons · May 22, 2023 · 3ffeb07 · 3ffeb07
1 parent 293530b
commit 3ffeb07
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Showing 2 changed files with 67 additions and 18 deletions.
diff --git a/stm32-modules/include/tempdeck-gen3/tempdeck-gen3/thermal_task.hpp b/stm32-modules/include/tempdeck-gen3/tempdeck-gen3/thermal_task.hpp
@@ -210,24 +210,14 @@ class ThermalTask {
         _readings.last_tick = message.timestamp;
         // Reading conversion
 
-        auto res = _converter.convert(_readings.plate_adc_1);
-        if (std::holds_alternative<double>(res)) {
-            _readings.plate_temp_1 = std::get<double>(res);
-        } else {
-            _readings.plate_temp_1 = 0.0F;
-        }
-        res = _converter.convert(_readings.plate_adc_2);
-        if (std::holds_alternative<double>(res)) {
-            _readings.plate_temp_2 = std::get<double>(res);
-        } else {
-            _readings.plate_temp_2 = 0.0F;
-        }
-        res = _converter.convert(_readings.heatsink_adc);
-        if (std::holds_alternative<double>(res)) {
-            _readings.heatsink_temp = std::get<double>(res);
-        } else {
-            _readings.heatsink_temp = 0.0F;
-        }
+        _readings.heatsink_temp = convert_thermistor(message.heatsink, false);
+        auto heatsink_temp = _readings.heatsink_temp.has_value()
+                                 ? _readings.heatsink_temp.value()
+                                 : 0;
+        _readings.plate_temp_1 =
+            convert_thermistor(message.plate_1, true, heatsink_temp);
+        _readings.plate_temp_2 =
+            convert_thermistor(message.plate_2, true, heatsink_temp);
 
         _readings.peltier_current_milliamps =
             PeltierReadback::adc_to_milliamps(message.imeas);
@@ -411,6 +401,7 @@ class ThermalTask {
             constants.c = message.c.value();
         }
 
+        _offset_constants = constants;
         auto ret = _eeprom.write_offset_constants(constants, policy);
         if (ret) {
             // Succesful, so overwrite the task's constants
@@ -529,6 +520,23 @@ class ThermalTask {
         }
     }
 
+    auto convert_thermistor(uint32_t raw_reading, bool add_offsets,
+                            double heatsink_temp = 0.0)
+        -> std::optional<double> {
+        auto res = _converter.convert(raw_reading);
+        if (!std::holds_alternative<double>(res)) {
+            return std::nullopt;
+        }
+        double reading = std::get<double>(res);
+        if (add_offsets) {
+            double offset = (_offset_constants.a * heatsink_temp) +
+                            (_offset_constants.b * reading) +
+                            (_offset_constants.c);
+            reading += offset;
+        }
+        return reading;
+    }
+
     Queue& _message_queue;
     Aggregator* _task_registry;
     ThermalReadings _readings;

diff --git a/stm32-modules/tempdeck-gen3/tests/test_thermal_task.cpp b/stm32-modules/tempdeck-gen3/tests/test_thermal_task.cpp
@@ -580,6 +580,47 @@ TEST_CASE("thermal task offset constants message handling") {
     }
 }
 
+TEST_CASE("thermal task offset constant compensation") {
+    auto *tasks = tasks::BuildTasks();
+    TestThermalPolicy policy;
+    eeprom::Eeprom<decltype(tasks->_thermal_task)::EEPROM_ADDRESS> eeprom;
+    thermistor_conversion::Conversion<lookups::KS103J2G> converter(
+        decltype(tasks->_thermal_task)::THERMISTOR_CIRCUIT_BIAS_RESISTANCE_KOHM,
+        decltype(tasks->_thermal_task)::ADC_BIT_MAX, false);
+    GIVEN("a set of offset constants") {
+        double a = GENERATE(0, -0.5, 0.5);
+        double b = GENERATE(0, -0.5, 0.5);
+        double c = GENERATE(0, -0.5, 0.5);
+        auto constants = eeprom::OffsetConstants{.a = a, .b = b, .c = c};
+        REQUIRE(eeprom.write_offset_constants(constants, policy));
+        WHEN("receiving a new temperature reading") {
+            static constexpr double PLATE_TEMP = 25.0;
+            static constexpr double HEATSINK_TEMP = 50.0;
+            auto thermistors_msg = messages::ThermistorReadings{
+                .timestamp = 1000,
+                .plate_1 = converter.backconvert(PLATE_TEMP),
+                .plate_2 = converter.backconvert(PLATE_TEMP),
+                .heatsink = converter.backconvert(HEATSINK_TEMP),
+                .imeas = 555,
+            };
+            tasks->_thermal_queue.backing_deque.push_back(thermistors_msg);
+            tasks->_thermal_task.run_once(policy);
+            THEN("the readings are updated properly") {
+                // Alg is READING = (A * heatsink) + ((B+1) * plate) + C
+                double expected =
+                    (a * HEATSINK_TEMP) + ((b + 1.0) * PLATE_TEMP) + c;
+                auto readings = tasks->_thermal_task.get_readings();
+                REQUIRE_THAT(readings.heatsink_temp.value(),
+                             Catch::Matchers::WithinAbs(HEATSINK_TEMP, 0.1));
+                REQUIRE_THAT(readings.plate_temp_1.value(),
+                             Catch::Matchers::WithinAbs(expected, 0.1));
+                REQUIRE_THAT(readings.plate_temp_2.value(),
+                             Catch::Matchers::WithinAbs(expected, 0.1));
+            }
+        }
+    }
+}
+
 TEST_CASE("thermal task power debug functionality") {
     auto *tasks = tasks::BuildTasks();
     TestThermalPolicy policy;