{"product_id":"st400pc-intelligent-measurement-control-and-protection-device","title":"ST400PC Intelligent Measurement, Control, and Protection Device","description":"\u003ch1\u003eST400‑PC \/ ST400‑PT Microcomputer Measurement‑Control and Protection Device\u003c\/h1\u003e\n\u003ch2\u003eProduct Overview\u003c\/h2\u003e\n\u003cp\u003e    The ST400‑PC and ST400‑PT are microcomputer measurement‑control \u0026amp; protection devices manufactured by Wanlong Electric Group. ST400‑PC is applied for PC current‑protection circuits while ST400‑PT is designed for PT voltage monitoring circuits. The device integrates protection, electrical measurement, circuit‑breaker control, alarm processing and industrial communication functions. It features local man‑machine LCD operation panel with Chinese‑English bilingual display, 4‑20 mA analog transmitter output, as well as local\/remote permission management. Typical application scenarios include medium‑low voltage switchgear cabinets, distribution rooms and industrial power monitoring systems. Default user access password is \u003cstrong\u003e0400\u003c\/strong\u003e.\u003c\/p\u003e\n\u003ch2\u003eProduct Models and Classification\u003c\/h2\u003e\n\u003ch3\u003eST400‑PC Model Coding (For PC protection circuit)\u003c\/h3\u003e\n\u003cp\u003e   Example model: \u003ccode\u003eST400PC‑F‑2‑5A‑100V‑M1\u003c\/code\u003e\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003eControl circuit voltage type\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cul\u003e\n\u003cli\u003eF: Standard type\u003c\/li\u003e\n\u003cli\u003eM: AC enhanced type (DC110V)\u003c\/li\u003e\n\u003cli\u003eH1: DC enhanced type (DC110V)\u003c\/li\u003e\n\u003cli\u003eH2: DC enhanced type (DC220V)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003col start=\"2\"\u003e\n\u003cli\u003eCommunication protocol code\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cul\u003e\n\u003cli\u003e1: No communication\u003c\/li\u003e\n\u003cli\u003e2: 2‑channel Profibus‑DP\u003c\/li\u003e\n\u003cli\u003e3: 1‑channel Modbus‑RTU\u003c\/li\u003e\n\u003cli\u003e5: 2‑channel Modbus‑RTU\u003c\/li\u003e\n\u003cli\u003e6: 2‑channel Profibus‑DP\u003c\/li\u003e\n\u003cli\u003e7: 1‑channel Modbus‑RTU + 1‑channel Profibus‑DP\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003col start=\"3\"\u003e\n\u003cli\u003eCurrent grade: 1A, 5A (built‑in CT input range)\u003c\/li\u003e\n\u003cli\u003eVoltage grade: 100V, 400V\u003c\/li\u003e\n\u003cli\u003eOptional extended functions\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cul\u003e\n\u003cli\u003eM1: 1‑channel analog output; M2: 2‑channel analog output\u003c\/li\u003e\n\u003cli\u003eL: Zero‑sequence current input; Uz: Zero‑sequence voltage input ‑4DI: Extended 4 digital inputs; 2DO: Extended 2 relay outputs\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eST400‑PT Model Coding (For PT voltage circuit)\u003c\/h3\u003e\n\u003cp\u003e    Model coding rules keep consistent with ST400‑PC. The PT version removes front‑panel physical local‑remote permission switch; front‑panel close and trip buttons have no functional definition for PT units.\u003c\/p\u003e\n\u003ch2\u003eCore Protection Functions\u003c\/h2\u003e\n\u003cp\u003e    Over‑current Protection Two‑stage over‑current protection is available, including 1st‑stage over‑current and 2nd‑stage over‑current. Pick‑up value and action delay are configurable; action modes can be set as Disable, Alarm or Trip. Time resolution for protection delay is 0.02 s.\u003c\/p\u003e\n\u003cp\u003e   Zero‑sequence Protection Zero‑sequence current and zero‑sequence voltage protection are supported. Users configure threshold and action mode (disable \/ alarm \/ trip) to detect earth‑related insulation faults.\u003c\/p\u003e\n\u003cp\u003e   Voltage Related Protection Covers over‑voltage, under‑voltage, voltage unbalance and PT disconnection protection. Protection thresholds and action modes are adjustable for busbar voltage abnormality monitoring.\u003c\/p\u003e\n\u003cp\u003e   Auto‑reclosure Three‑phase one‑shot auto‑reclosure function can be enabled or disabled according to field configuration.\u003c\/p\u003e\n\u003cp\u003e   Circuit‑breaker Loop Supervision Detects close‑circuit and trip‑circuit wire break condition; function enable and external divider wiring are required for valid loop break detection.\u003c\/p\u003e\n\u003ch2\u003eMeasurement and Metering Functions\u003c\/h2\u003e\n\u003cp\u003e    Analog Sampling Measurement Real‑time measuring of three‑phase current, three‑phase voltage, zero‑sequence current, zero‑sequence voltage, frequency, active\/reactive\/apparent power and power factor. CT primary \/ PT primary and secondary ratio parameters shall match with site instrument transformers for accurate reading.\u003c\/p\u003e\n\u003cp\u003e    4‑20 mA Analog Transmitter Output Supports configurable AO variables, output range 4‑20 mA. Calculation formula: \\(I_{out}= \\frac{DisplayValue‑AO_{low}}{AO_{high}‑AO_{low}} \\times16 +4\\) For power‑related variables: DisplayValue = Raw reading × CT ratio × PT ratio. AO upper and lower limits are user‑configurable.\u003c\/p\u003e\n\u003ch2\u003eInput \u0026amp; Output Functions\u003c\/h2\u003e\n\u003cp\u003e    Digital Input (DI) DI channels accept external status signals: circuit‑breaker position feedback, spring charged status, local‑remote switching signal and general‑purpose digital input. DI status can be checked on device panel for commissioning.\u003c\/p\u003e\n\u003cp\u003e   Relay Output (DO) Multiple logic relay outputs are configurable: general alarm, definite‑time over‑current output, zero‑sequence voltage output, self‑diagnostic fault output, busbar loss‑voltage output, trip output, logic outputs and general‑purpose relay outputs. DO function assignment shall be completed in parameter menu.\u003c\/p\u003e\n\u003ch2\u003eOperation and Maintenance Functions\u003c\/h2\u003e\n\u003cp\u003e   Local‑Remote Permission Switch ST400‑PC supports physical panel permission toggle switch. Permission can also be assigned via DI terminal or menu setting. PT model does not carry hardware permission switch. Improper permission setting will block local panel or remote communication control commands.\u003c\/p\u003e\n\u003cp\u003e   Human‑Machine Interface LCD display supports Chinese \/ English language switch. Navigation keys include up \/ down \/ left \/ right, confirm, return, reset, close and trip buttons. LED status indicators show power status, fault, alarm and communication running status.\u003c\/p\u003e\n\u003cp\u003e   Fault Diagnosis Typical diagnostic items include permission switching abnormality, measured value deviation, close\/trip loop break fault and communication connection failure. The device provides menu‑based troubleshooting guidance. Event and fault information can be viewed locally on panel.\u003c\/p\u003e\n\u003ch2\u003eCommunication Capability\u003c\/h2\u003e\n\u003cp\u003e   Modbus‑RTU Dual‑network A\/B Modbus‑RTU interface. Device address, baud rate (4.8 \/ 9.6 \/19.2 \/38.4 kbps) are configurable. Remote close command: write register 00AF with value AAAA; remote trip: write 5555; emergency trip: write 3333.\u003c\/p\u003e\n\u003cp\u003e   Profibus‑DP Requires GSD file \u003ccode\u003eSIDA08F4.GSD\u003c\/code\u003e for system configuration. After entering Data‑Exchange state, send value 1000 for close, 2000 for normal trip and 8000 for emergency trip. Terminating resistor shall be correctly installed on Profibus bus. Communication documents, point tables and GSD files can be acquired from Wanlong Electric Group technical support.\u003c\/p\u003e\n\u003ch2\u003eInstallation and Mechanical Parameters\u003c\/h2\u003e\n\u003cp\u003e   Panel Cut‑out Dimension: \u003cstrong\u003e134 mm × 134 mm\u003c\/strong\u003e Terminal blocks include relay output terminals, CT current input terminals, PT voltage input terminals, DI input terminals, communication terminals, AO analog output terminals, PE protective earth terminal and extended‑function terminals.\u003c\/p\u003e","brand":"Wan Long Electric","offers":[{"title":"宽 161mm，高 184mm，壳体深度 133.6mm \/ 浅灰 \/ 标准","offer_id":45255395999810,"sku":null,"price":240.0,"currency_code":"USD","in_stock":false},{"title":"宽 161mm，高 184mm，壳体深度 133.6mm \/ 浅灰 \/ 交流增强 DC110V；直流增强 DC110V；直流增强 DC220V","offer_id":45255396032578,"sku":null,"price":240.0,"currency_code":"USD","in_stock":false},{"title":"宽 161mm，高 184mm，壳体深度 133.6mm \/ 浅灰 \/ 测量输入电压量程二档：100V、400V","offer_id":45255396065346,"sku":null,"price":240.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0688\/1221\/0242\/files\/69.png?v=1790058551","url":"https:\/\/wanlongelectric.com\/products\/st400pc-intelligent-measurement-control-and-protection-device","provider":"Wan Long Electric Group Co., Ltd.","version":"1.0","type":"link"}