diff --git a/apps/chrg/applications/thread/chrg_comm.c b/apps/chrg/applications/thread/chrg_comm.c
index 284e1a4..3fb70e6 100644
--- a/apps/chrg/applications/thread/chrg_comm.c
+++ b/apps/chrg/applications/thread/chrg_comm.c
@@ -586,7 +586,7 @@ eMBException funcWriteMultipleCoils (rt_uint8_t *reqFrame, rt_uint16_t reqLen,
 	}
 
 	memcpy(resFrame, reqFrame, reqLen);
-	*resLen = reqLen-2;
+	*resLen = 6;
 
 	eRegStatus = eMBRegCoilsCB(reqFrame, &resFrame[3], regAddress, cntCoils, MB_REG_WRITE);
 	if (eRegStatus != MB_ENOERR) {
@@ -620,7 +620,7 @@ eMBException funcWriteMultipleHoldingRegister (rt_uint8_t *reqFrame, rt_uint16_t
 	}
 
 	memcpy(resFrame, reqFrame, reqLen);
-	*resLen = reqLen-2;
+	*resLen = 6;
 
 	eRegStatus = eMBRegHoldingCB(reqFrame, &resFrame[3], regAddress, cntReg, MB_REG_WRITE);
 	if (eRegStatus != MB_ENOERR) {