diff --git a/dynamixel_manager/src/dyn_manager.c b/dynamixel_manager/src/dyn_manager.c
index 18046e5b85501aae1be41a863c3fe3fcecdbcfbb..ba83d0e7b27d1f9364fbd401ebaa2591a1689dbd 100644
--- a/dynamixel_manager/src/dyn_manager.c
+++ b/dynamixel_manager/src/dyn_manager.c
@@ -89,7 +89,7 @@ unsigned char dyn_manager_id_present(unsigned char num,unsigned char *ids,unsign
 
 void dyn_manager_delete_op_single_master(TDynManager *manager,unsigned char master_index,OP_HANDLE *op)
 {
-  unsigned char j,k,delete;
+  unsigned char j,k,del;
 
   if(op->op_index[master_index]!=0xFF)
   {
@@ -197,11 +197,11 @@ void dyn_manager_delete_op_single_master(TDynManager *manager,unsigned char mast
   else
     op->op_index[master_index]=0xFF;
   // remove handles
-  delete=0x01;
+  del=0x01;
   for(j=0;j<manager->num_masters;j++)
     if(op->op_index[j]!=0xFF)
-      delete=0x00;
-  if(delete==0x01)
+      del=0x00;
+  if(del==0x01)
   {
     op->op_type=no_op;
     manager->num_ops--;
@@ -470,14 +470,14 @@ OP_HANDLE *dyn_manager_single_op_new(TDynManager *manager,unsigned char mode,uns
   if((op_handle=dyn_manager_get_free_op_handle(manager))==0x00000000)
     return 0x00000000;
   if(mode==DYN_MANAGER_READ || mode==DYN_MANAGER_WRITE)
-    op_handle->op_type=DYN_MANAGER_SINGLE|mode;
+    op_handle->op_type=(op_type_t)(DYN_MANAGER_SINGLE|mode);
   else
     return 0x00000000;
   current_op_index=manager->operations[master_index].num_single_op;
   if(current_op_index<DYN_MANAGER_MAX_NUM_SINGLE_OP)
   {
     current_op=&manager->operations[master_index].single_op[current_op_index];
-    current_op->common.operation=DYN_MANAGER_SINGLE|mode;
+    current_op->common.operation=(op_type_t)(DYN_MANAGER_SINGLE|mode);
     current_op->common.op_handle=op_handle;
     current_op->id=id;
     current_op->address=address;
@@ -549,7 +549,7 @@ OP_HANDLE *dyn_manager_sync_op_new(TDynManager *manager,unsigned char mode,unsig
   if((op_handle=dyn_manager_get_free_op_handle(manager))==0x00000000)
     return 0x00000000;
   if(mode==DYN_MANAGER_READ || mode==DYN_MANAGER_WRITE)
-    op_handle->op_type=DYN_MANAGER_SYNC|mode;
+    op_handle->op_type=(op_type_t)(DYN_MANAGER_SYNC|mode);
   else
     return 0x00000000;
   for(i=0;i<num;i++)
@@ -568,7 +568,7 @@ OP_HANDLE *dyn_manager_sync_op_new(TDynManager *manager,unsigned char mode,unsig
         if(dyn_manager_id_present(current_op->num_devices,current_op->ids,ids[i])==0x00)
         {
           op_handle->op_index[master_index]=current_op_index;
-          current_op->common.operation=DYN_MANAGER_SYNC|mode;
+          current_op->common.operation=(op_type_t)(DYN_MANAGER_SYNC|mode);
           current_op->common.op_handle=op_handle;
           current_op->address=address;
           current_op->length=length;
@@ -713,7 +713,7 @@ OP_HANDLE *dyn_manager_bulk_op_new(TDynManager *manager,unsigned char mode,unsig
   if((op_handle=dyn_manager_get_free_op_handle(manager))==0x00000000)
     return 0x00000000;
   if(mode==DYN_MANAGER_READ || mode==DYN_MANAGER_WRITE)
-    op_handle->op_type=DYN_MANAGER_BULK|mode;
+    op_handle->op_type=(op_type_t)(DYN_MANAGER_BULK|mode);
   else
     return 0x00000000;
   for(i=0;i<num;i++)
@@ -732,7 +732,7 @@ OP_HANDLE *dyn_manager_bulk_op_new(TDynManager *manager,unsigned char mode,unsig
         if(dyn_manager_id_present(current_op->num_devices,current_op->ids,ids[i])==0x00)
         {
           op_handle->op_index[master_index]=current_op_index;
-          current_op->common.operation=DYN_MANAGER_BULK|mode;
+          current_op->common.operation=(op_type_t)(DYN_MANAGER_BULK|mode);
           current_op->common.op_handle=op_handle;
           current_op->address[current_op->num_devices]=address[i];
           current_op->length[current_op->num_devices]=length[i];