diff --git a/app/src/main/java/com/yinuo/safetywatcher/watcher/constant/GasConstants.kt b/app/src/main/java/com/yinuo/safetywatcher/watcher/constant/GasConstants.kt
deleted file mode 100644
index 4f02dcc..0000000
--- a/app/src/main/java/com/yinuo/safetywatcher/watcher/constant/GasConstants.kt
+++ /dev/null
@@ -1,70 +0,0 @@
-package com.yinuo.safetywatcher.watcher.constant
-
-import com.common.commonlib.utils.MMKVUtils
-
-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
-
-val default_map = hashMapOf<String, Float>(
-    Pair("CO_min", CO_MIN),
-    Pair("CO_max", CO_MAX),
-    Pair("O2_min", O2_MIN),
-    Pair("O2_max", O2_MAX),
-    Pair("CH4_min", CH4_MIN),
-    Pair("CH4_max", CH4_MAX),
-    Pair("H2S_min", H2S_MIN),
-    Pair("H2S_max", H2S_MAX)
-)
-
-fun getLowThresHoldKey(gasType: String): String {
-    return "${gasType.uppercase()}_min"
-}
-
-fun getHighThresHoldKey(gasType: String): String {
-    return "${gasType.uppercase()}_max"
-}
-
-fun saveLowThreshold(gasType: String, value: Float){
-    MMKVUtils.put(getLowThresHoldKey(gasType), value)
-}
-
-fun saveHighThreshold(gasType: String, value: Float){
-    MMKVUtils.put(getHighThresHoldKey(gasType), value)
-}
-
-fun getGasLowThreshold(gasType: String): Float {
-    val lowThresholdKey = getLowThresHoldKey(gasType)
-    val float = MMKVUtils.getFloat(lowThresholdKey)
-    if (float <= 0) {
-        return default_map[lowThresholdKey] ?: -1f
-    }
-    return float
-}
-
-fun getGasHighThreshold(gasType: String): Float {
-    val highThresholdKey = getHighThresHoldKey(gasType)
-    val float = MMKVUtils.getFloat(highThresholdKey)
-    if (float <= 0) {
-        return default_map[highThresholdKey] ?: -1f
-    }
-    return float
-}
-
-fun getGasUnit(gasType: String): String {
-    return when (gasType.uppercase()) {
-        "CO" -> "ppm"
-        "O2" -> "%VOL"
-        "CH4" -> "%LEL"
-        "H2S" -> "ppm"
-        else -> ""
-    }
-}
\ No newline at end of file
diff --git a/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasUtils.kt b/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasPortUtils.kt
similarity index 98%
rename from app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasUtils.kt
rename to app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasPortUtils.kt
index 9dca4d7..2b08017 100644
--- a/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasUtils.kt
+++ b/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasPortUtils.kt
@@ -8,7 +8,7 @@ import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 
-object GasUtils {
+object GasPortUtils {
     private const val BAUD_RATE = 9600
     private const val PORT_PATH = "/dev/ttyS1"
     const val FULL_MSG_SIZE = 25
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
new file mode 100644
index 0000000..e326bbf
--- /dev/null
+++ b/app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasUtilss.kt
@@ -0,0 +1,102 @@
+package com.yinuo.safetywatcher.watcher.port
+
+import com.common.commonlib.utils.MMKVUtils
+import com.yinuo.safetywatcher.watcher.port.cmd.CH4
+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"
+}
+
+private fun getHighThresHoldKey(gasType: String): String {
+    return "${gasType.uppercase()}_$MAX_SUFFIX"
+}
+
+/**
+ * 存储告警阈值低值
+ */
+fun saveLowThreshold(gasType: String, value: Float) {
+    MMKVUtils.put(getLowThresHoldKey(gasType), value)
+}
+
+/**
+ * 存储告警阈值高值
+ */
+fun saveHighThreshold(gasType: String, value: Float) {
+    MMKVUtils.put(getHighThresHoldKey(gasType), value)
+}
+
+/**
+ * 获取高度阈值低值
+ */
+fun getGasLowThreshold(gasType: String): Float {
+    val lowThresholdKey = getLowThresHoldKey(gasType)
+    val float = MMKVUtils.getFloat(lowThresholdKey)
+    if (float <= 0) {
+        return default_threshold_map[lowThresholdKey] ?: -1f
+    }
+    return float
+}
+
+/**
+ * 获取告警阈值高值
+ */
+fun getGasHighThreshold(gasType: String): Float {
+    val highThresholdKey = getHighThresHoldKey(gasType)
+    val float = MMKVUtils.getFloat(highThresholdKey)
+    if (float <= 0) {
+        return default_threshold_map[highThresholdKey] ?: -1f
+    }
+    return float
+}
+
+
+/**
+ * 获取本地气体单位
+ */
+fun getLocalGasUnit(gasType: String): String {
+    return when (gasType.uppercase()) {
+        O2 -> "%VOL"
+        CO, CH4, H2S -> getDefaultUnit(gasType)
+        else -> ""
+    }
+}
+
+private fun getDefaultUnit(gasType: String): String {
+    val localUnit = MMKVUtils.getString("unit_$gasType")
+    if (!localUnit.isNullOrEmpty()) {
+        return localUnit
+    }
+    return "ppm"
+}
\ No newline at end of file
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 b59ba56..6c4d27a 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
@@ -11,8 +11,6 @@ import com.common.serialport.utils.HexUtils
 import com.yinuo.library.vlc.TxtOverlay
 import com.yinuo.library.vlc.utils.LogUtils
 import com.yinuo.safetywatcher.watcher.constant.GAS_CLOUD_UPLOAD_SIZE_ONCE
-import com.yinuo.safetywatcher.watcher.constant.getGasHighThreshold
-import com.yinuo.safetywatcher.watcher.constant.getGasLowThreshold
 import com.yinuo.safetywatcher.watcher.net.DevicesApi
 import com.yinuo.safetywatcher.watcher.port.cmd.CH4
 import com.yinuo.safetywatcher.watcher.port.cmd.CO
@@ -40,7 +38,7 @@ object ParseHelper {
 
     fun parse(it: ByteArray) {
         try {
-            if (it.isNotEmpty() && it.size >= GasUtils.FULL_MSG_SIZE) {
+            if (it.isNotEmpty() && it.size >= GasPortUtils.FULL_MSG_SIZE) {
                 LogUtils.v("receive msg, ${HexUtils.byteArrToHex(it)}")
                 val gasIndex = it[0].toInt()
                 val status = it[14].toInt()
@@ -86,7 +84,7 @@ object ParseHelper {
         if (unitBinaryString.length < 16) {
             val offset = 16 - unitBinaryString.length
             repeat(offset) {
-                unitBinaryString = "0" + unitBinaryString;
+                unitBinaryString = "0$unitBinaryString"
             }
         }
         unitBinaryString = unitBinaryString.reversed()
@@ -237,7 +235,7 @@ object ParseHelper {
         flagRunnable = FlagRunnable(gasName)
         mPortRunnable[index] = flagRunnable
         // 如果一段时间内没有收到消息，认为连接断开
-        mHandler.postDelayed(flagRunnable, GasUtils.CHECK_TIME)
+        mHandler.postDelayed(flagRunnable, GasPortUtils.CHECK_TIME)
     }
 
     /**
diff --git a/app/src/main/java/com/yinuo/safetywatcher/watcher/ui/HomeActivity.kt b/app/src/main/java/com/yinuo/safetywatcher/watcher/ui/HomeActivity.kt
index 4bd345d..f79e3a4 100644
--- a/app/src/main/java/com/yinuo/safetywatcher/watcher/ui/HomeActivity.kt
+++ b/app/src/main/java/com/yinuo/safetywatcher/watcher/ui/HomeActivity.kt
@@ -21,7 +21,7 @@ import com.yinuo.safetywatcher.watcher.constant.DELAY_TIME_CHECK_CAMERA
 import com.yinuo.safetywatcher.watcher.constant.DELAY_TIME_CHECK_SENSOR
 import com.yinuo.safetywatcher.watcher.constant.DELAY_TIME_OPEN_CAMERA
 import com.yinuo.safetywatcher.watcher.constant.STORAGE_WARN_THRESHOLD
-import com.yinuo.safetywatcher.watcher.port.GasUtils
+import com.yinuo.safetywatcher.watcher.port.GasPortUtils
 import com.yinuo.safetywatcher.watcher.services.HeartbeatService
 import com.yinuo.safetywatcher.watcher.ui.view.ConfirmDialog
 import com.yinuo.safetywatcher.watcher.utils.BatteryHelper
@@ -172,7 +172,7 @@ class HomeActivity : NoOptionsActivity() {
             watchSensor(DELAY_TIME_CHECK_SENSOR)
         }
         watchSensor(DELAY_TIME_CHECK_SENSOR)
-        GasUtils.initPort()
+        GasPortUtils.initPort()
     }
 
     /**
@@ -216,7 +216,7 @@ class HomeActivity : NoOptionsActivity() {
         LogUtils.w("watchSensorRunnable start")
         AppData.setSensorData(false)
         changeViewStatus()
-        GasUtils.initPort()
+        GasPortUtils.initPort()
         watchSensor(DELAY_TIME_CHECK_SENSOR)
     }
 
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 b3eeaac..964a40f 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
@@ -1,15 +1,14 @@
 package com.yinuo.safetywatcher.watcher.ui
 
 import android.view.View
-import android.widget.Toast
 import com.yinuo.safetywatcher.R
 import com.yinuo.safetywatcher.databinding.ActivitySensorThresholdBinding
 import com.yinuo.safetywatcher.watcher.base.NoOptionsActivity
-import com.yinuo.safetywatcher.watcher.constant.getGasHighThreshold
-import com.yinuo.safetywatcher.watcher.constant.getGasLowThreshold
-import com.yinuo.safetywatcher.watcher.constant.getGasUnit
-import com.yinuo.safetywatcher.watcher.constant.saveHighThreshold
-import com.yinuo.safetywatcher.watcher.constant.saveLowThreshold
+import com.yinuo.safetywatcher.watcher.port.getGasHighThreshold
+import com.yinuo.safetywatcher.watcher.port.getGasLowThreshold
+import com.yinuo.safetywatcher.watcher.port.getLocalGasUnit
+import com.yinuo.safetywatcher.watcher.port.saveHighThreshold
+import com.yinuo.safetywatcher.watcher.port.saveLowThreshold
 import com.yinuo.safetywatcher.watcher.utils.showToast
 
 class SensorThresholdSetActivity : NoOptionsActivity() {
@@ -28,7 +27,7 @@ class SensorThresholdSetActivity : NoOptionsActivity() {
 
     override fun initView() {
         gasName = intent.getStringExtra("GasType")!!
-        val gasUnit = getGasUnit(gasName)
+        val gasUnit = getLocalGasUnit(gasName)
         mBinding.tvMin.append("$gasUnit)")
         mBinding.tvMax.append("$gasUnit)")