From 70cde175081f92259d6174bab073d98555de9952 Mon Sep 17 00:00:00 2001
From: William Clark <wrvc96@gmail.com>
Date: Mon, 5 Dec 2022 12:40:07 +0000
Subject: [PATCH] first draft cjc

---
 core/th7/service.go          | 27 +++++++++++++++++++++++++++
 thermocouple/thermocouple.go | 25 +++++++++++++++++++++++++
 2 files changed, 52 insertions(+)

diff --git a/core/th7/service.go b/core/th7/service.go
index 5bda8f6..adf7bf6 100644
--- a/core/th7/service.go
+++ b/core/th7/service.go
@@ -2,6 +2,8 @@ package th7
 
 import (
 	"fmt"
+	"log"
+	"th7/thermocouple"
 	"time"
 )
 
@@ -69,6 +71,31 @@ func startCacheService(t *TH7Adapter) {
 		}
 
 		// read pcb temp and apply CJC
+		// the board temperature wont noticeably change for the ~300 ms of sampling
+		// so only reading pcb temp and applying cjc after this duration
+		// probably wont affect the readings.
+		pcb_temperature := t.pcbPort.ReadPCBTemp()
+
+		for k := range t.cfg.Channels {
+
+			tc := t.cfg.Channels[k].Thermo
+			if thermocouple.WithinTemperatureRange(tc, pcb_temperature) {
+				// if we can apply CJC with this configuration ...
+				cjc_uv, err := thermocouple.UV(tc, pcb_temperature)
+				if err != nil {
+					log.Println("Error doing CJC", err)
+					continue
+				}
+
+				data[k].Value -= cjc_uv
+				data[k].Unit = t.cfg.Channels[k].Unit
+			} else {
+				// CJC can not be applied
+				// board temp out of range for specified thermocouple type
+				// perhaps just subtract board temperature?  dont know
+				fmt.Println("No valid CJC", t.cfg.Channels[k])
+			}
+		}
 
 		t.mu.Lock()
 		t.data = data
diff --git a/thermocouple/thermocouple.go b/thermocouple/thermocouple.go
index 1e72d70..369b78e 100644
--- a/thermocouple/thermocouple.go
+++ b/thermocouple/thermocouple.go
@@ -4,6 +4,31 @@ import (
 	"th7/data/thermocouple"
 )
 
+func WithinTemperatureRange(thermo thermocouple.Type, c float64) bool {
+
+	switch thermo {
+	case thermocouple.B:
+		return c >= B_MIN_C && c <= B_MAX_C
+	case thermocouple.E:
+		return c >= E_MIN_C && c <= E_MAX_C
+	case thermocouple.J:
+		return c >= J_MIN_C && c <= J_MAX_C
+	case thermocouple.K:
+		return c >= K_MIN_C && c <= K_MAX_C
+	case thermocouple.N:
+		return c >= N_MIN_C && c <= N_MAX_C
+	case thermocouple.R:
+		return c >= R_MIN_C && c <= R_MAX_C
+	case thermocouple.S:
+		return c >= S_MIN_C && c <= S_MAX_C
+	case thermocouple.T:
+		return c >= T_MIN_C && c <= T_MAX_C
+	}
+
+	// None type
+	return false
+}
+
 func C(thermo thermocouple.Type, uv float64) (float64, error) {
 
 	switch thermo {