The straight-forward wire drawing machine is one of the more difficult to control straight wire drawing machines. It draws the wire by multiple motors at the same time, so the operation efficiency is very high. Since it is drawn by multiple motors at the same time, after the wire is wound on the previous reel for several times, it directly enters the next wire drawing die and is wound on the next reel without passing any wire guide pulley in the middle. The wire between the reels is basically linear, so there are high requirements on the synchronization of the motor and the rapidity of the dynamic response.

The core problem of straight-forward wire drawing machine control is that when the wire passes through each stage of drawing, the diameter of the wire changes. In order to ensure the tension on the wire, the speed of the rear stage needs to be in a certain proportion to the front stage. In the case of knowing the speed of the previous stage, since the volume of the material passing through the die is fixed in unit time, that is, the volume of the material is fixed.The "flow rate" is fixed and can be calculated from the linear speed of the front stage,the diameter of the drawing die, etc., so that the speed required by the latter stage can be obtained.

In theory, the wire drawing operation can be successfully completed by realizing the precise matching of speeds at all levels. However, due to problems such as changes in motor speed, wire slippage on the tower wheel, and mold wear, the speed matching will change and tension will be generated. Fluctuations, these disturbances are detected by the tension feedback sensor of the current stage, as the feedback amount of the PID controller, after the PID performs calculation, it adjusts the output frequency of the inverter to eliminate the tension change caused by the disturbance. 

In this system, the synchronous speed is sent by the PLC to the inverters of all levels by means of analog or communication, and the first one runs at a given speed (the number of fixed speed stages can be configured as two adjacent stages as required) , the PID adjustment of other levels is completed by the inverter of this level. This can reduce the configuration of expensive AD modules for PLCs while realizing system functions.