下位机（PLC）程序控制主要负责数据采集、比例阀控制等。

The functions of PLC are data collecting, valve controlling and so on.

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比例阀也可以被用来控制压力。

Proportional valves can also be used to control pressure.

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液压控制技术：液压方向、压力、流量控制阀、比例阀、球阀。

Hydraulic control technology: hydraulic direction, pressure, flow control valve, proportional valve, ball valve.

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液压控制技术：液压方向、压力、流量控制阀、比例阀、球阀。

Hydraulic control technology: hydraulic direction, pressure, flow control valve, proportional valve, ball valve.

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