摘要
In large fusion experiments, such as tokamak devices, there is a common trendfor slow control systems. Because of complexity of the plants, the so-called 'Standard Model' (SM)in slow control has been adopted on several tokamak machines. This model is based on a three-levelhierarchical control: 1) High-Level Control (HLC) with a supervisory function; 2) Medium-LevelControl (MLC) to interface and concentrate I/O field equipments; 3) Low-Level Control (LLC) withhard real-time I/O function, often managed by PLCs. FTU control system designed with SM concepts hasunderwent several stages of developments in its fifteen years duration of runs. The latestevolution was inevitable, due to the obsolescence of the MLC CPUs, based on VME-MOTOROLA 68030 withOS9 operating system. A large amount of C code was developed for that platform to route the dataflow from LLC, which is constituted by 24 Westinghouse Numalogic PC-700 PLCs with about 8000field-points, to HLC, based on a commercial Object-Oriented Real-Time database on Alpha/CompaqTru64platform. Therefore, we have to look for cost-effective solutions and finally a CompactPCI—Intelx86 platform with Linux operating system was chosen. A software porting has been done, taking intoaccount the differences between OS9 and Linux operating system in terms of Inter/Network ProcessesCommunications and I/O multi-ports serial driver. This paper describes the hardware/softwarearchitecture of the new MLC system, emphasizing the reliability and the low costs of the open sourcesolutions. Moreover, a huge amount of software packages available in open source environment willassure a less painful maintenance, and will open the way to further improvements of the systemitself.
In large fusion experiments, such as tokamak devices, there is a common trendfor slow control systems. Because of complexity of the plants, the so-called 'Standard Model' (SM)in slow control has been adopted on several tokamak machines. This model is based on a three-levelhierarchical control: 1) High-Level Control (HLC) with a supervisory function; 2) Medium-LevelControl (MLC) to interface and concentrate I/O field equipments; 3) Low-Level Control (LLC) withhard real-time I/O function, often managed by PLCs. FTU control system designed with SM concepts hasunderwent several stages of developments in its fifteen years duration of runs. The latestevolution was inevitable, due to the obsolescence of the MLC CPUs, based on VME-MOTOROLA 68030 withOS9 operating system. A large amount of C code was developed for that platform to route the dataflow from LLC, which is constituted by 24 Westinghouse Numalogic PC-700 PLCs with about 8000field-points, to HLC, based on a commercial Object-Oriented Real-Time database on Alpha/CompaqTru64platform. Therefore, we have to look for cost-effective solutions and finally a CompactPCI—Intelx86 platform with Linux operating system was chosen. A software porting has been done, taking intoaccount the differences between OS9 and Linux operating system in terms of Inter/Network ProcessesCommunications and I/O multi-ports serial driver. This paper describes the hardware/softwarearchitecture of the new MLC system, emphasizing the reliability and the low costs of the open sourcesolutions. Moreover, a huge amount of software packages available in open source environment willassure a less painful maintenance, and will open the way to further improvements of the systemitself.
