The logic control switch quantity
This is the most fundamental and most extensive PLC application domain, it is replacing the traditional relay circuit, realize logic control, sequence control, which can be used for the control of a single device, can also be used to control and automation line more machines. Such as injection molding machine, printing machine, a stapler, combination machine tools, grinding spurt, packaging production line, electroplating line etc.
Analog control
In industrial production process, there are many changes, such as temperature, pressure, and flow, liquid level and speed are simulated. In order to make the programmable controller processing Analog, must realize Analog/Digital and Analog to produce stats () () of Digital between the A/D conversion and D/A transformation. PLC manufacturer production supporting the A/D and D/A conversion module, make the programmable controller for analog control.
Exercise control
PLC can be used in circular motion or linear motion control. From control configuration, early directly to switch I/O modules connected position sensor and actuator, now generally use special movement control module. If can drive stepping motor servo motor or the uniaxial or multi-axis position control module. The world of major PLC control functions are almost, widely used in all kinds of machinery, machine tool, robots, elevator, etc.
Process control
Refers to the process control of temperature, pressure, and flow rate analog closed-loop control. As industrial controlling computer, PLC can prepare all kinds of control algorithm procedures, complete closed-loop control. The PID closed-loop control system is usually USES morer adjustment methods. There are large and medium-sized PLC, many small PID module has the function of PLC module. PID processing is generally run special PID subroutines. Process control in metallurgy, chemical, heat treatment, so there is widely used.