diff --git a/library/common/common.c b/library/common/common.c
index bb30ae3..eacac22 100644
--- a/library/common/common.c
+++ b/library/common/common.c
@@ -105,13 +105,13 @@ char *Rd_GetBuildTime(void)
     return g_sBuildTime;
 }
 
-uint16_t Rd_modbusCRC16(char *data, uint8_t length)
+uint16_t Rd_modbusCRC16(const uint8_t *data, uint16_t length)
 {
     uint16_t crc = 0xFFFF;
 
-    for (uint8_t i = 0; i < length; i++)
+    for (uint16_t i = 0; i < length; i++)
     {
-        crc ^= (uint16_t)data[i];
+        crc ^= (uint16_t)data[i]; 
 
         for (uint8_t j = 0; j < 8; j++)
         {
diff --git a/library/common/include/common.h b/library/common/include/common.h
index b69d6fc..5419730 100644
--- a/library/common/include/common.h
+++ b/library/common/include/common.h
@@ -158,7 +158,7 @@ int Rd_Array2String(char *_pRes, int _iLen, char *_pSrc[], int _iNum, char *_Ptr
 int Rd_FileExists(const char *_psPath);
 int Rd_RegularFileExists(const char *_psPath);
 char *Rd_GetBuildTime(void);
-uint16_t Rd_modbusCRC16(char *data, uint8_t length);
+uint16_t Rd_modbusCRC16(const uint8_t *data, uint16_t length);
 
 #ifdef BUILD_LOG
 extern void Rd_ElogEnableStrong(void);