The "digital" control system, composed of a Programmable Logic Controller (PLC), pressure sensors, and pressure gauges, primarily implements the following three functions on the HPHT Hydraulic Cubic Press apparatus:
1、Realizing the logical control of electrical actions: This refers to controlling the sequence of actions of executive components (such as solenoid valves) in the electrical system, ensuring they are energized according to the press operation steps. Compared to traditional relay logical control, the PLC can realize the required functions in real-time by compiling a ladder diagram and is more flexible when needing to modify or add/delete the energization sequence of solenoid valves.
2、Realizing pressure control and fault diagnosis: This includes the precise control of the hydraulic system and pressure parameters, as well as the rapid judgment of system anomalies. For example, the system can use the pressure gauge, a "digital" system, to adjust the throttle valve to obtain six-cylinder synchronous pressure. In terms of fault diagnosis, the system can retrieve operating statuses and abnormal phenomena via the touch screen (such as the state of the booster travel switch contacts or the phenomenon of taking too long to reach overpressure), thereby inferring the fault cause and locating the specific component.
3、Realizing the execution and storage of process parameter curves: The digital system enables the press apparatus to operate according to preset process curves (such as the technology curve for synthesizing diamond with powder catalyst, shown in Figure 2). Operators can set various parameters via the touch screen, such as overpressure pressure, starting heating pressure, pause time, final pressure, and soaking time, and precisely correspond power or voltage to different time periods, thus transforming the original unknown and passive control method into an active control method. Simultaneously, the system can also store these process parameter curves.