diff --git a/app/modules/tmr.c b/app/modules/tmr.c
index 1af81695..142ecc7c 100755
--- a/app/modules/tmr.c
+++ b/app/modules/tmr.c
@@ -60,6 +60,15 @@ tmr.softwd(int)
 #define TIMER_MODE_AUTO 1
 #define TIMER_IDLE_FLAG (1<<7) 
 
+#define STRINGIFY_VAL(x) #x
+#define STRINGIFY(x) STRINGIFY_VAL(x)
+
+// assuming system_timer_reinit() has *not* been called
+#define MAX_TIMEOUT_DEF 6870947  //SDK 1.5.3 limit (0x68D7A3)
+
+static const uint32 MAX_TIMEOUT=MAX_TIMEOUT_DEF;
+static const char* MAX_TIMEOUT_ERR_STR = "Range: 1-"STRINGIFY(MAX_TIMEOUT_DEF);
+
 typedef struct{
 	os_timer_t os;
 	sint32_t lua_ref;
@@ -129,16 +138,13 @@ static int tmr_now(lua_State* L){
 // Lua: tmr.register( id, interval, mode, function )
 static int tmr_register(lua_State* L){
 	uint32_t id = luaL_checkinteger(L, 1);
-	MOD_CHECK_ID(tmr, id);
-	sint32_t interval = luaL_checkinteger(L, 2);
+	uint32_t interval = luaL_checkinteger(L, 2);
 	uint8_t mode = luaL_checkinteger(L, 3);
-	//validate arguments
-    const int32_t MAX_TIMEOUT = 0xC49BA5; // assuming system_timer_reinit() has *not* been called
-	uint8_t args_invalid = (interval <= 0 || interval > MAX_TIMEOUT)
-		|| (mode != TIMER_MODE_SINGLE && mode != TIMER_MODE_SEMI && mode != TIMER_MODE_AUTO)
-		|| (lua_type(L, 4) != LUA_TFUNCTION && lua_type(L, 4) != LUA_TLIGHTFUNCTION);
-	if(args_invalid)
-		return luaL_error(L, "wrong arg range");
+	//Check if provided parameters are valid
+	MOD_CHECK_ID(tmr, id);
+	luaL_argcheck(L, (interval > 0 && interval <= MAX_TIMEOUT), 2, MAX_TIMEOUT_ERR_STR);
+  luaL_argcheck(L, (mode == TIMER_MODE_SINGLE || mode == TIMER_MODE_SEMI || mode == TIMER_MODE_AUTO), 3, "Invalid mode");
+  luaL_argcheck(L, (lua_type(L, 4) == LUA_TFUNCTION || lua_type(L, 4) == LUA_TLIGHTFUNCTION), 4, "Must be function");
 	//get the lua function reference
 	lua_pushvalue(L, 4);
 	sint32_t ref = luaL_ref(L, LUA_REGISTRYINDEX);
@@ -212,9 +218,8 @@ static int tmr_interval(lua_State* L){
 	uint8_t id = luaL_checkinteger(L, 1);
 	MOD_CHECK_ID(tmr,id);
 	timer_t tmr = &alarm_timers[id];
-	sint32_t interval = luaL_checkinteger(L, 2);
-	if(interval <= 0)
-		return luaL_error(L, "wrong arg range");
+	uint32_t interval = luaL_checkinteger(L, 2);
+  luaL_argcheck(L, (interval > 0 && interval <= MAX_TIMEOUT), 2, MAX_TIMEOUT_ERR_STR);
 	if(tmr->mode != TIMER_MODE_OFF){	
 		tmr->interval = interval;
 		if(!(tmr->mode&TIMER_IDLE_FLAG)){
diff --git a/docs/en/modules/tmr.md b/docs/en/modules/tmr.md
index 7dab8cc0..bf17acc6 100644
--- a/docs/en/modules/tmr.md
+++ b/docs/en/modules/tmr.md
@@ -19,7 +19,7 @@ To free up the resources with this timer when done using it, call [`tmr.unregist
 
 #### Parameters
 - `id` timer id (0-6)
-- `interval_ms` timer interval in milliseconds. Maximum value is 12884901. In SDKs <= 1.5.0 values >6871948 result in incorrect behaviour.
+- `interval_ms` timer interval in milliseconds. Maximum value is 6870947 (1:54:30.947).
 - `mode` timer mode:
 	- `tmr.ALARM_SINGLE` a one-shot alarm (and no need to call [`tmr.unregister()`](#tmrunregister))
 	- `tmr.ALARM_SEMI` manually repeating alarm (call [`tmr.start()`](#tmrstart) to restart)
@@ -68,7 +68,7 @@ Changes a registered timer's expiry interval.
 
 #### Parameters
 - `id` timer id (0-6)
-- `interval_ms` new timer interval in milliseconds. Maximum value is 12884901. In SDKs <= 1.5.0 values >6871948 result in incorrect behaviour.
+- `interval_ms` new timer interval in milliseconds. Maximum value is 6870947 (1:54:30.947).
 
 #### Returns
 `nil`
@@ -109,7 +109,7 @@ To free up the resources with this timer when done using it, call [`tmr.unregist
 
 #### Parameters
 - `id` timer id (0-6)
-- `interval_ms` timer interval in milliseconds. Maximum value is 12884901. In SDKs <= 1.5.0 values >6871948 result in incorrect behaviour.
+- `interval_ms` timer interval in milliseconds. Maximum value is 6870947 (1:54:30.947).
 - `mode` timer mode:
 	- `tmr.ALARM_SINGLE` a one-shot alarm (and no need to call [`tmr.unregister()`](#tmrunregister))
 	- `tmr.ALARM_SEMI` manually repeating alarm (call [`tmr.start()`](#tmrunregister) to restart)
@@ -273,4 +273,4 @@ The event-driven model of NodeMCU means that there is no need to be sitting in h
 none
 
 #### Returns
-`nil`
\ No newline at end of file
+`nil`