diff --git a/components/zcancmder/zcan_protocol_parser.cpp b/components/zcancmder/zcan_protocol_parser.cpp
index 25cdf6a..4923af5 100644
--- a/components/zcancmder/zcan_protocol_parser.cpp
+++ b/components/zcancmder/zcan_protocol_parser.cpp
@@ -147,6 +147,10 @@ void ZCanProtocolParser::_onRceivePacket(ZIModule* module, zcr_cmd_header_t* rxc
   if (module == nullptr) return err::koperation_not_support; \
   if (paraNum >= 0 && paraNum != cxt->paramlen / 4) return err::kcmd_param_num_error;
 
+  #define GET_MODULE(paraNum)                        \
+  auto* module = dynamic_cast<MODULE_CLASS*>(cxt->module);   \
+  if (module == nullptr) return err::koperation_not_support; 
+
 #define MODULE_CLASS ZIModule
 int32_t ZCanProtocolParser::module_ping(cmdcontxt_t* cxt) {
   CHECK_AND_GET_MODULE(0);
@@ -225,7 +229,7 @@ int32_t ZCanProtocolParser::step_motor_easy_move_to(cmdcontxt_t* cxt) {
   return module->step_motor_easy_move_to(cxt->params[0]);
 }
 int32_t ZCanProtocolParser::step_motor_easy_move_to_zero(cmdcontxt_t* cxt) {
-  CHECK_AND_GET_MODULE(0);
+  GET_MODULE(0);
   return module->step_motor_easy_move_to_zero();
 }
 int32_t ZCanProtocolParser::step_motor_easy_set_current_pos(cmdcontxt_t* cxt) {