To provide an extension device for a process control computer that enables a low-cost function enhancement even in an old process control computer that can not be connected to a general-purpose network, only through the fabrication of function adding S/W, while keeping the existing S/W intact.
A computer 1 has a remote DMA 7 for bypassing a CPU to access data on a memory 3 under external control. A PC 9 as a functional extension to the computer 1 has a remote DMA adapter 10 connected to the remote DMA 7, and an additional function application 28 for acquiring data from the memory 3 via the remote DMA adapter 10 and remote DMA 7 and processing the acquired data as an additional function. The data processed by the additional function application 28 are written into the memory 3 of the computer 1 via the remote DMA adapter 10 and remote DMA 7.
Toshihide Kodama
Takenaka Ikuo
Keigo Murakami