Update read_write.py

- position length bug fixed.

Author: ROBOTIS-zerom

python/tests/protocol1_0/read_write.py

@@ -116,15 +116,15 @@ def getch():
         break
 
     # Write goal position
-    dxl_comm_result, dxl_error = packetHandler.write4ByteTxRx(portHandler, DXL_ID, ADDR_MX_GOAL_POSITION, dxl_goal_position[index])
+    dxl_comm_result, dxl_error = packetHandler.write2ByteTxRx(portHandler, DXL_ID, ADDR_MX_GOAL_POSITION, dxl_goal_position[index])
     if dxl_comm_result != COMM_SUCCESS:
         print("%s" % packetHandler.getTxRxResult(dxl_comm_result))
     elif dxl_error != 0:
         print("%s" % packetHandler.getRxPacketError(dxl_error))
 
     while 1:
         # Read present position
-        dxl_present_position, dxl_comm_result, dxl_error = packetHandler.read4ByteTxRx(portHandler, DXL_ID, ADDR_MX_PRESENT_POSITION)
+        dxl_present_position, dxl_comm_result, dxl_error = packetHandler.read2ByteTxRx(portHandler, DXL_ID, ADDR_MX_PRESENT_POSITION)
         if dxl_comm_result != COMM_SUCCESS:
             print("%s" % packetHandler.getTxRxResult(dxl_comm_result))
         elif dxl_error != 0: