1.Architecture

Plasma control system is one of the most essential system for EAST experimental operation. It is constructed of Linux cluster with two server machines as shown in Figure 1. Host machine provides user account management, parameter setting GUI, running and operation log message, data saving and restoring service. While the computing node runs the control algorithms for real-time plasma parameter adjusting. At present, the EAST PCS is configured with seven real time processes running on seven corresponding physical CPU cores. The fastest control cycle is 100 micro-seconds. There are two sets of RFM (Reflected memory) network for diagnostic data input and control command output. All the actuator systems, such as gas puffing, power supply, heating system and so on, are controlled by PCS in such digital communication way, which ensures the high-quality signal transmission and plasma control performance.

Figure 1. Hardware architecture of EAST PCS

2.Functions

After more than ten years of development, PCS has 16 control categories (nearly 30 control algorithms) controlling plasma current, position, shape, density, radiation, profile and so on, which only had 5 control categories (6 algorithms in total) when adopted from DIII-D PCS in 2005. As shown in figure 2, the red blocks present the new added control categories and functions from 2005, while the blue ones are the original categories. EAST PCS plays an important role for the EAST device safe operation and achievements of remarkable records.

Figure 2. Main control categories and algorithms in EAST PCS

3.Modification

In 2021, the radiation calculation subsystem has completed the upgrade work, including server machine replacement and the application of ITER RTF for the software upgrade. The hardware and software test based on historical experiment data has been finished. Another upgrade work is constructing fast vertical displacement feedback control system based on D-TACQ 2106 high-speed acquisition equipment. The new control system has been tested and the control cycle for fast vertical displacement can be speeded up to 50 micro seconds. These two upgrade systems will be applied in the 2021 EAST operation campaign.

4.Location

The PCS cluster is located in the EAST data acquisition computer room. The RFM switches are located in the EAST data acquisition computer room and EAST core data center.

5.Specification of EAST PCS

• • fastest control cycle: 100 us
  • synchronous acquisition channels: 288
  • control categories: 16
  • control algorithms: 30
  • real-time equilibrium reconstruction: 500 us