Chapter 85 covers electric motors, electrical equipment and parts thereof; sound recorders and reproducers, television image and sound recorders and reproducers, and parts and accessories thereof. This chapter is the most concentrated chapter of electromechanical products in the HS classification, involving various electrical devices such as power generation, transformation, energy storage, power utilization, communication, and control. Products within the chapter are listed under different headings according to function and technical characteristics, such as 8501 electric motors, 8504 transformers, 8535 high-voltage switches, 8536 low-voltage switches, 8537 control panels, etc. The chapter notes contain special provisions for semiconductors, integrated circuits, etc., and classification requires comprehensive judgment based on chapter notes and heading notes. Heading 8537 covers boards, panels, consoles, desks, cabinets and other bases, equipped with two or more apparatus of heading 8535 or 8536, or a combination of apparatus of heading 8535 or 8536 with apparatus of heading 8501, 8504, etc., for electric control or the distribution of electricity, but for a voltage not exceeding 1,000 V. This heading includes industrial control cabinets, distribution boards, operation consoles, control boxes, etc., whose core feature is the integration of multiple switching, protection, or control elements to achieve the distribution and protection of electrical energy or automatic control of equipment. 8537 does not include simple bases equipped with only a single switch or fuse, nor similar devices for a voltage exceeding 1,000 V (classified under 8538). First 2 digits 85: indicates Chapter 85, i.e., electric motors, electrical equipment and parts thereof; sound recorders and reproducers, television image and sound recorders and reproducers, and parts and accessories thereof. Digits 3-4, 37: indicates heading 8537, i.e., boards, panels, consoles, desks, cabinets and other bases, equipped with two or more apparatus of heading 8535 or 8536, or a combination of apparatus of heading 8535 or 8536 with apparatus of heading 8501, 8504, etc., for electric control or the distribution of electricity, but for a voltage not exceeding 1,000 V. Digits 5-6, 10: indicates subheading 8537.10, i.e., programmable controllers (PLC). This subheading specifically refers to electronic devices with programmable memory for executing instructions such as logic operations, sequence control, timing, counting and arithmetic operations, and controlling various machines or production processes through digital or analog input/output. PLCs generally consist of a power supply, CPU, input/output modules, programmer, etc., and are core equipment for industrial automation. Programmable controllers (PLC) are classified under 8537.10 rather than 8543 or 8538 because they are essentially control panels/cabinets equipped with multiple switching, relay, transistor and other control elements, and have programmable functions, meeting the description of heading 8537. PLCs generally integrate power supply modules, CPU modules, I/O modules, etc., and belong to the electrical control bases under 8537 that are 'equipped with two or more apparatus of heading 8535 or 8536.' Compared with 8543 (other electrical equipment not elsewhere specified), PLCs have a clearly named subheading; compared with 8538 (parts exclusively for 8535-8537), PLCs are complete control devices rather than parts.

Product Name: The standard name of the declared commodity; 'Programmable Controller' or 'PLC' should be filled in, along with brand and model. Use: Explain the specific application scenario of the PLC, such as industrial automation control, machine tool control, production line control, etc. Brand: Fill in the manufacturer or brand name, such as Siemens, Mitsubishi, Omron, etc. Model: Fill in the specific model, such as S7-1200, FX3U, CJ2M, etc., which should be consistent with the physical nameplate. Voltage: Fill in the rated operating voltage of the PLC, typically 24V DC or 220V AC, and must be below 1,000V. Programmable: Confirm whether it has programmable memory and can execute user-written programs; usually fill in 'Yes'. Composition: Briefly describe the main components, such as CPU module, power supply module, input/output modules, etc. I/O Points: Fill in the number of digital or analog I/O points, such as 14 inputs/10 outputs, reflecting the control scale. Customs declaration example: Product Name: Programmable Controller (PLC) Brand: Siemens Model: S7-1200 CPU 1214C Use: For logic control of automated production lines Voltage: 24V DC Programmable: Yes Composition: CPU module, power supply module, digital input/output modules I/O Points: 14 inputs/10 outputs HS Code: 8537.10.00 Mistakenly classifying PLC under 8543 (other electrical equipment), ignoring the named subheading 8537.10. Declaring PLC parts (such as I/O modules) separately as 8537.10, when they should actually be classified under 8538. Failing to distinguish PLC from DCS (distributed control system); DCS is also generally classified under 8537.10, but attention must be paid to functional differences. Declaring voltage exceeding 1,000V, resulting in classification under 8538 instead of 8537. Misreporting a relay board with only simple logic as a PLC, when it should actually be classified under 8536.

Core classification criteria: First, confirm whether the commodity is a board, panel, console, desk, cabinet, screen or other base for electric control or the distribution of electricity, equipped with at least two apparatus of heading 8535 or 8536, or a combination of 8535/8536 with 8501/8504 apparatus. Second, the voltage must not exceed 1,000V. Third, it must have programmable memory capable of executing instructions such as logic operations, sequence control, timing, counting, etc., and control external equipment through input/output. Fourth, the commodity must be a complete device, not a part. If the above conditions are met, it is classified under 8537.10. If it is a part, it is classified under 8538; if the voltage exceeds 1,000V, it is classified under 8538; if it is a fixed logic controller, it may be classified under 8536 or other subheadings of 8537. 8538 Parts exclusively for 8535, 8536, 8537: 8538 is for parts, such as PLC I/O modules and CPU modules when imported separately; while 8537.10 is for complete PLC devices. 8543 Electrical equipment not elsewhere specified: 8543 is a residual heading; PLCs already have a clearly named subheading 8537.10, so they are not classified under 8543. 8536 Switches, relays, etc., for voltage ≤1,000V: 8536 is for individual switches, relays and other components; PLCs are control devices integrating multiple components and are programmable. 8471 Automatic data processing equipment: 8471 is for computers and other data processing equipment; PLCs are specifically for industrial control and, although programmable, are not general-purpose computers. 8535 Switches and protection devices for voltage >1,000V: 8535 is for high voltage; PLCs are generally used for low voltage (≤1,000V); high-voltage control cabinets are classified under 8535 or 8538. Is it equipped with at least two apparatus of heading 8535 or 8536? Is the voltage not exceeding 1,000V? Does it have programmable memory? Is it a complete device rather than a part? Is it used for electric control or the distribution of electricity?

Is there a difference in HS classification between PLC and DCS? Both are generally classified under 8537.10, as both are programmable control devices. However, DCS emphasizes distributed control; if its composition includes multiple PLCs or control stations, it may be classified as a complete system, still under 8537.10. If DCS modules are imported separately, they are classified under 8538. Under which code should a PLC I/O module be classified when imported separately? As a dedicated part of a PLC, an I/O module imported separately should be classified under 8538.90 (parts exclusively for 8535-8537). However, if imported together with the PLC main unit and assembled into a complete device, the whole is classified under 8537.10. How to determine whether a controller is a programmable controller (PLC)? The key is whether it has programmable memory, allowing users to write programs to implement logic, sequence, timing, counting and other functions. Fixed-logic relay boards or simple sequence controllers are not PLCs and should be classified under 8536 or other subheadings of 8537. How should a PLC be classified when its voltage exceeds 1,000V? If the PLC operating voltage exceeds 1,000V, it does not meet the conditions of heading 8537 (8537 is limited to ≤1,000V) and should be classified under 8538 (parts exclusively for 8535-8537) or 8535 (high-voltage switching apparatus), depending on the function. How to distinguish PLC from industrial computer (IPC) in classification? Industrial computers are generally classified under 8471 (automatic data processing equipment), while PLCs are classified under 8537.10. Key distinction: PLCs are designed specifically for industrial control with programmable logic control functions and typically do not run general-purpose operating systems; IPCs have general-purpose computing capabilities. Under which code should a PLC programmer (hand-held programmer) be classified? A hand-held programmer, if a dedicated programming device, is generally classified under 8537.10 (as an accessory of a PLC) or 8543 (other electrical equipment). However, if it is a general-purpose computer, it is classified under 8471. It is recommended to judge based on function and whether it is dedicated to PLCs. When importing a PLC, how should 'Composition' be filled in the declaration elements? The main modules should be listed, such as CPU module, power supply module, input/output modules, communication modules, etc. If it is a complete set of knocked-down parts, indicate 'complete set of knocked-down parts' and the specific modules. Avoid writing only 'complete set' or 'see list'. Does 8537.10 include PLC expansion racks and baseplates? If expansion racks and baseplates are dedicated parts of a PLC and imported separately, they are classified under 8538; if they form a complete control cabinet together with the PLC main unit, the whole is classified under 8537.10. Judgment should be based on the import state and function.