The PLC language which IEC organization standardized as IEC 61131-3 standard is used in various fields of industry such as robot control system and industry automation system. However, it can't provide suitable development environments for developers who don't have enough knowledge about robot devices. Besides, it is difficult to support branch code, real-time operation and to interpret without extensive device knowledge. For these reasons, this paper provides useful development architecture for easy development and well-defined interfaces. Especially, we more focus on block diagram model in order for application developers to easily construct their applications. Our architecture model support development environment based on block diagram model. It can be possible to provide robot developer with reliable development environments.