Abstract : This paper introduces an X-ray industrial television control system based on PLC and frequency converter, detailing its system composition, working principle, and software design method. This control system can significantly improve the working speed and accuracy of the X-ray industrial television inspection system, while reducing labor intensity. Keywords : PLC; frequency converter; X-ray inspection 0 Introduction In the domestic spiral welded pipe industry, X-ray industrial television is generally used to inspect the quality of steel pipe welds. During the inspection process, the X-ray generator and imaging system remain stationary, while the steel pipe rotates laterally on the inspection trolley rollers, and the inspection trolley travels longitudinally, thus displaying the weld image on the television screen for the inspector to view. The original control system relied entirely on the operator manipulating two potentiometers to control the speed in two directions, which was difficult to operate and hard to achieve proportional operation of the two speeds. This paper designs a practical control system using PLC and frequency converter, achieving proportional operation of the two speeds and reducing the operator's workload. 1 System Composition The system composition is shown in Figure 1. The control core is a PLC, which calculates the required frequency for the two frequency converters and controls their operation. This, in turn, drives the X-ray inspection cart and rotates the rollers via motors and reducers. The PLCs are Mitsubishi products: FX2N-64MR+ with extensions FX2N-8EX and FX2N-16EYT. The FX2N-64MR has 32 dead inputs and 32 relay outputs, used for inputs to switches, buttons, limit switches, and to control indicator lights, intermediate relays, solenoid valves, and the operating status of the frequency converters. The FX2N-8EX has eight dead inputs, accepting inputs from a two-digit decimal DIP switch for inputting the forming angle. The FX2N-16EYT has 16 transistor outputs used to control the operating frequency of the two frequency converters. The frequency converters are Mitsubishi products FR-540-1.5KAC400V1.5kW and FR-540-11K AC400V11kW. Both frequency converters are equipped with FR-A5AX digital input ports, driving a 1.5kW longitudinal travel motor for the inspection cart and two 5kW idler roller rotation motors, respectively, to rotate the steel pipe laterally. Two potentiometers are used for fine-tuning the frequency converter's operating frequency. [b][align=center]For more details, please click: Speed ​​Synthesis and Control of X-ray Industrial Television Inspection System[/align][/b]