diff --git a/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasConstants.kt b/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasConstants.kt
new file mode 100644
index 0000000..ac407f6
--- /dev/null
+++ b/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasConstants.kt
@@ -0,0 +1,107 @@
+package com.yinuo.safetywatcher.watcher.port
+
+import com.yinuo.safetywatcher.watcher.port.cmd.CH4
+import com.yinuo.safetywatcher.watcher.port.cmd.CO
+import com.yinuo.safetywatcher.watcher.port.cmd.H2S
+
+// 后缀
+const val MIN_SUFFIX = "min"
+const val MAX_SUFFIX = "max"
+
+// 各个气体报警高低默认值，默认单位
+// ppm -1代表不考虑低值
+const val CO_MIN = -1f
+
+// 20mg/m3
+const val CO_MAX_MGM3 = 20f
+
+//vol
+const val O2_MIN = 19.5f
+const val O2_MAX = 23.5f
+
+//lel
+const val CH4_MIN = -1f
+const val CH4_MAX_LEL = 25f
+
+//ppm
+const val H2S_MIN = -1f
+
+// 10mg/m3
+const val H2S_MAX_MGM3 = 10f
+
+// 单位
+const val UNIT_VOL = "%VOL"
+const val UNIT_PPM = "ppm"
+const val UNIT_MGM3 = "mg/m3"
+const val UNIT_LEL = "%LEL"
+
+/**
+ * 气体分子质量
+ */
+const val MOLECULAR_CO = 28
+const val MOLECULAR_H2S = 34
+const val MOLECULAR_CH4 = 16
+
+val molecular_map = hashMapOf<String, Int>(
+    Pair(CO, MOLECULAR_CO),
+    Pair(CH4, MOLECULAR_CH4),
+    Pair(H2S, MOLECULAR_H2S),
+)
+
+/**
+ * ppm单位的气体量程
+ */
+val gas_range_ppm = hashMapOf<String, String>(
+    Pair(CO, "0-1000 $UNIT_PPM"),
+    Pair(CH4, "0-50000 $UNIT_PPM"),
+    Pair(H2S, "0-100 $UNIT_PPM")
+)
+
+/**
+ * mg/m3单位的气体量程
+ *
+ * ppm -> mg/m3   X=M.C/22.4
+ * X—污染物以每标立方米的毫克数表示的浓度值；
+ * C—污染物以 ppm 表示的浓度值；
+ * M—污染物的分之子量。
+ *
+ * CO分子量 = 28    28/22.4 * 1000
+ * CH4分子量 = 16   16/22.4 * 50000
+ * H2S分子量 = 34   34/22.4 * 100
+ */
+val gas_range_mgm3 = hashMapOf<String, String>(
+    Pair(CO, "0-1250 $UNIT_MGM3"),
+    Pair(CH4, "0-35714 $UNIT_MGM3"),
+    Pair(H2S, "0-151 $UNIT_MGM3")
+)
+
+/**
+ * 氧气的量程
+ */
+const val O2_RANGE = "0-30 $UNIT_VOL"
+
+
+// 气体默认阈值表
+val default_threshold_map_ppm = hashMapOf<String, Float>(
+    Pair("${CO}_$MIN_SUFFIX", CO_MIN),
+    Pair("${CO}_$MAX_SUFFIX", mgm3ToPpm(CO_MAX_MGM3, MOLECULAR_CO)),
+    Pair("${CH4}_$MIN_SUFFIX", CH4_MIN),
+    Pair("${CH4}_$MAX_SUFFIX", ch4Lel2ppm(CH4_MAX_LEL)),
+    Pair("${H2S}_$MIN_SUFFIX", H2S_MIN),
+    Pair("${H2S}_$MAX_SUFFIX", mgm3ToPpm(H2S_MAX_MGM3, MOLECULAR_H2S))
+)
+
+// 气体默认阈值表
+val default_threshold_map_mgm3 = hashMapOf<String, Float>(
+    Pair("${CO}_$MIN_SUFFIX", CO_MIN),
+    Pair("${CO}_$MAX_SUFFIX", CO_MAX_MGM3),
+    Pair("${CH4}_$MIN_SUFFIX", CH4_MIN),
+    Pair("${CH4}_$MAX_SUFFIX", ppm2mgm3(ch4Lel2ppm(CH4_MAX_LEL), MOLECULAR_CH4)),
+    Pair("${H2S}_$MIN_SUFFIX", H2S_MIN),
+    Pair("${H2S}_$MAX_SUFFIX", H2S_MAX_MGM3)
+)
+
+val default_threshold_map_unit = hashMapOf<String, HashMap<String, Float>>(
+    Pair(UNIT_PPM, default_threshold_map_ppm),
+    Pair(UNIT_MGM3, default_threshold_map_mgm3),
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasUtilss.kt b/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasUtilss.kt
index c4e3bcc..a63a2f9 100644
--- a/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasUtilss.kt
+++ b/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasUtilss.kt
@@ -6,35 +6,6 @@ import com.yinuo.safetywatcher.watcher.port.cmd.CO
 import com.yinuo.safetywatcher.watcher.port.cmd.H2S
 import com.yinuo.safetywatcher.watcher.port.cmd.O2
 
-// 后缀
-const val MIN_SUFFIX = "min"
-const val MAX_SUFFIX = "max"
-
-// 各个气体报警高低默认值，默认单位
-const val CO_MIN = 0f
-const val CO_MAX = 0f
-
-const val O2_MIN = 0f
-const val O2_MAX = 0f
-
-const val CH4_MIN = 0f
-const val CH4_MAX = 0f
-
-const val H2S_MIN = 0f
-const val H2S_MAX = 0f
-
-// 气体默认阈值表
-val default_threshold_map = hashMapOf<String, Float>(
-    Pair("${CO}_$MIN_SUFFIX", CO_MIN),
-    Pair("${CO}_$MAX_SUFFIX", CO_MAX),
-    Pair("${O2}_$MIN_SUFFIX", O2_MIN),
-    Pair("${O2}_$MAX_SUFFIX", O2_MAX),
-    Pair("${CH4}_$MIN_SUFFIX", CH4_MIN),
-    Pair("${CH4}_$MAX_SUFFIX", CH4_MAX),
-    Pair("${H2S}_$MIN_SUFFIX", H2S_MIN),
-    Pair("${H2S}_$MAX_SUFFIX", H2S_MAX)
-)
-
 private fun getLowThresHoldKey(gasType: String): String {
     return "${gasType.uppercase()}_$MIN_SUFFIX"
 }
@@ -44,49 +15,80 @@ private fun getHighThresHoldKey(gasType: String): String {
 }
 
 /**
- * 存储告警阈值低值
+ * 存储告警阈值低值 保证存储的是ppm单位
+ * 氧气是vol单位
  */
-fun saveLowThreshold(gasType: String, value: Float) {
-    MMKVUtils.put(getLowThresHoldKey(gasType), value)
+fun saveLowThreshold(gasType: String, value: Float, localGasUnit: String) {
+    var localValue = value
+    if (O2 != gasType && UNIT_MGM3 == localGasUnit) {
+        val molecular = molecular_map[gasType]
+        molecular?.let {
+            localValue = mgm3ToPpm(value, it)
+        }
+    }
+    MMKVUtils.put(getLowThresHoldKey(gasType), localValue)
 }
 
 /**
- * 存储告警阈值高值
+ * 存储告警阈值高值 保证存储的是ppm单位
+ * 氧气是vol单位
  */
-fun saveHighThreshold(gasType: String, value: Float) {
-    MMKVUtils.put(getHighThresHoldKey(gasType), value)
+fun saveHighThreshold(gasType: String, value: Float, localGasUnit: String) {
+    var localValue = value
+    if (O2 != gasType && UNIT_MGM3 == localGasUnit) {
+        val molecular = molecular_map[gasType]
+        molecular?.let {
+            localValue = mgm3ToPpm(value, it)
+        }
+    }
+    MMKVUtils.put(getHighThresHoldKey(gasType), localValue)
 }
 
 /**
  * 获取高度阈值低值
  */
-fun getGasLowThreshold(gasType: String): Float {
+fun getGasLowThreshold(gasType: String, unit: String): Float {
     val lowThresholdKey = getLowThresHoldKey(gasType)
-    val float = MMKVUtils.getFloat(lowThresholdKey)
-    if (float <= 0) {
-        return default_threshold_map[lowThresholdKey] ?: -1f
+    // ppm, 02 vol
+    var localVlaue = MMKVUtils.getFloat(lowThresholdKey)
+    if (localVlaue <= 0) {
+        // 氧气特殊处理
+        if (O2 == gasType) {
+            return O2_MIN
+        }
+        return (default_threshold_map_unit[unit])?.get(lowThresholdKey) ?: -1f
+    } else {
+        if (O2 != gasType && UNIT_MGM3 == unit) {
+            val molecular = molecular_map[gasType]
+            molecular?.let { localVlaue = ppm2mgm3(localVlaue, it) }
+        }
     }
-    return float
+    return localVlaue
 }
 
 /**
  * 获取告警阈值高值
  */
-fun getGasHighThreshold(gasType: String): Float {
+fun getGasHighThreshold(gasType: String, unit: String): Float {
     val highThresholdKey = getHighThresHoldKey(gasType)
-    val float = MMKVUtils.getFloat(highThresholdKey)
-    if (float <= 0) {
-        return default_threshold_map[highThresholdKey] ?: -1f
+    // ppm, O2 vol
+    var localVlaue = MMKVUtils.getFloat(highThresholdKey)
+    if (localVlaue <= 0) {
+        // 氧气特殊处理
+        if (O2 == gasType) {
+            return O2_MAX
+        }
+        return (default_threshold_map_unit[unit])?.get(highThresholdKey) ?: -1f
+    } else {
+        if (O2 != gasType && UNIT_MGM3 == unit) {
+            val molecular = molecular_map[gasType]
+            molecular?.let { localVlaue = ppm2mgm3(localVlaue, it) }
+        }
     }
-    return float
+    return localVlaue
 }
 
 
-const val UNIT_VOL = "%VOL"
-const val UNIT_PPM = "ppm"
-const val UNIT_MGM3 = "mg/m3"
-const val UNIT_LEL = "%LEL"
-
 /**
  * 获取本地气体单位
  */
@@ -110,45 +112,6 @@ fun saveGasUnit(gasType: String, unit: String) {
     MMKVUtils.put("unit_$gasType", unit)
 }
 
-/**
- * ppm单位的气体量程
- */
-val gas_range_ppm = hashMapOf<String, String>(
-    Pair(CO, "0-1000 $UNIT_PPM"),
-    Pair(CH4, "0-50000 $UNIT_PPM"),
-    Pair(H2S, "0-100 $UNIT_PPM")
-)
-
-/**
- * mg/m3单位的气体量程
- *
- * ppm -> mg/m3   X=M.C/22.4
- * X—污染物以每标立方米的毫克数表示的浓度值；
- * C—污染物以 ppm 表示的浓度值；
- * M—污染物的分之子量。
- *
- * CO分子量 = 28    28/22.4 * 1000
- * CH4分子量 = 16   16/22.4 * 50000
- * H2S分子量 = 34   34/22.4 * 100
- */
-val gas_range_mgm3 = hashMapOf<String, String>(
-    Pair(CO, "0-1250 $UNIT_MGM3"),
-    Pair(CH4, "0-35714 $UNIT_MGM3"),
-    Pair(H2S, "0-151 $UNIT_MGM3")
-)
-
-/**
- * 气体分子质量
- */
-const val MOLECULAR_CO = 28
-const val MOLECULAR_H2S = 34
-const val MOLECULAR_CH4 = 16
-
-/**
- * 氧气的量程
- */
-const val O2_RANGE = "0-30 $UNIT_VOL"
-
 /**
  * 获取气体传感器量程
  */
diff --git a/app/src/main/java/com/yinuo/safetywatcher/watcher/port/ParseHelper.kt b/app/src/main/java/com/yinuo/safetywatcher/watcher/port/ParseHelper.kt
index 53604f2..75f5ef2 100644
--- a/app/src/main/java/com/yinuo/safetywatcher/watcher/port/ParseHelper.kt
+++ b/app/src/main/java/com/yinuo/safetywatcher/watcher/port/ParseHelper.kt
@@ -150,8 +150,8 @@ object ParseHelper {
     private fun insertGasData(gasType: String, value: Float, unit: String) {
         GlobalScope.launch {
             // 阈值范围
-            val min = getGasLowThreshold(gasType)
-            val max = getGasHighThreshold(gasType)
+            val min = getGasLowThreshold(gasType, unit)
+            val max = getGasHighThreshold(gasType, unit)
 
             // 构造气体数据
             val timeMillis = System.currentTimeMillis()
diff --git a/app/src/main/java/com/yinuo/safetywatcher/watcher/ui/SensorThresholdSetActivity.kt b/app/src/main/java/com/yinuo/safetywatcher/watcher/ui/SensorThresholdSetActivity.kt
index 964a40f..f5c05c0 100644
--- a/app/src/main/java/com/yinuo/safetywatcher/watcher/ui/SensorThresholdSetActivity.kt
+++ b/app/src/main/java/com/yinuo/safetywatcher/watcher/ui/SensorThresholdSetActivity.kt
@@ -31,8 +31,8 @@ class SensorThresholdSetActivity : NoOptionsActivity() {
         mBinding.tvMin.append("$gasUnit)")
         mBinding.tvMax.append("$gasUnit)")
 
-        val gasLowThreshold = getGasLowThreshold(gasName)
-        val gasHighThreshold = getGasHighThreshold(gasName)
+        val gasLowThreshold = getGasLowThreshold(gasName, gasUnit)
+        val gasHighThreshold = getGasHighThreshold(gasName, gasUnit)
 
         if (gasLowThreshold > 0) {
             mBinding.etMin.setText(gasLowThreshold.toString())
@@ -52,12 +52,12 @@ class SensorThresholdSetActivity : NoOptionsActivity() {
         try {
             val min = mBinding.etMin.text.toString()
             if (min.isNotEmpty()) {
-                saveLowThreshold(gasName, min.toFloat())
+                saveLowThreshold(gasName, min.toFloat(), getLocalGasUnit(gasName))
             }
 
             val max = mBinding.etMax.text.toString()
             if (max.isNotEmpty()) {
-                saveHighThreshold(gasName, max.toFloat())
+                saveHighThreshold(gasName, max.toFloat(), getLocalGasUnit(gasName))
             }
         } catch (e: Exception) {
             showToast("只允许输入数值")