Yokogawa PW702

AC Input Electrical Parameters

Dual-Channel DC Output Parameters

Physical & Mechanical Parameters

Environmental Operating Parameters

Safety & EMC Certification

Function & Feature Highlights

1. Ultra-high power output capacity design, single module can carry large total rack load composed of high-density I/O modules and multi-redundant CPU modules, reducing the number of power supply modules required for large racks and saving cabinet internal installation space.
2. Dual-module parallel hot redundant load-sharing operation support, two PW702 modules installed in the same large DCS rack operate in load-sharing mode under normal working state, each module bears 50% of total rack power supply load; when one module suffers any fault shutdown, the other standby module automatically bears 100% full load within 2ms without any power supply interruption to DCS rack modules, meeting zero power interruption requirement of high-reliability continuous production process equipment.
3. Wide-range universal AC input design, stable DC output can be maintained under 85VAC~264VAC grid voltage fluctuation, fully adapting to industrial factory power grids with large voltage drop during peak production periods.
4. Built-in three-stage high-efficiency EMI filter structure arranged at AC input port, composed of double common-mode inductors, multi-group differential-mode capacitors and high-power absorption resistors, fully filtering high-frequency electromagnetic noise transmitted from industrial power grids, eliminating DCS high-speed bus communication packet loss and high-precision analog signal sampling distortion caused by severe power supply electromagnetic interference in large industrial plants.
5. Independent multi-stage hardware protection circuit for AC input terminal and each DC output channel, integrating input overvoltage/undervoltage protection, output overvoltage/undervoltage/overcurrent/short-circuit protection. When a single output channel is short-circuited, only the faulty channel stops power output, and the other channel maintains stable power supply to guarantee the normal operation of core triple redundant CPU and high-speed communication modules.
6. Front panel multi-group independent LED status indicator and digital fault code display window, including green power normal LED, red input fault LED, yellow output overload alarm LED, blue redundant synchronous state LED; 3-digit digital display window can display real-time input voltage value, each channel real-time output current value and fault code information, maintenance personnel can read detailed module operating data and fault cause information directly from front panel without disassembling the module or using external measuring instruments.
7. Built-in internal temperature real-time monitoring and automatic power derating logic. When the internal temperature rises above 62℃, the module automatically reduces the maximum total output power by 20% to lower internal power loss and heat generation; when the internal temperature exceeds 68℃, over-temperature protection is triggered to cut off all DC output power, preventing thermal breakdown of internal ultra-high-power power semiconductor components.
8. Hot-swappable modular design, PW702 module can be pulled out and replaced when the large DCS rack is in continuous normal operation without cutting off the entire cabinet power supply, during redundant module replacement process, the other standby module continuously undertakes all rack power supply load without power supply interruption, greatly shortening maintenance downtime of high-reliability large-scale continuous production process equipment.

Material & Structural Composition

1. Outer shell material: High-strength glass fiber reinforced flame-retardant ABS+PC alloy plastic, UL94 V-0 fire resistance grade, excellent anti-aging, anti-corrosion and impact resistance performance to adapt to large petrochemical plant main control room harsh environment.
2. Main circuit substrate: Six-layer high Tg FR4 flame-retardant copper-clad board, extra thick copper foil for high-current power transmission loops to minimize conduction heat generation and voltage drop under full-load high-current operation state.
3. Isolation conversion components: Large-capacity high-withstand-voltage high-frequency isolation switching transformer, multi-layer thick mica insulating paper separating primary and secondary windings to meet 2500VAC high-voltage isolation safety requirements; imported ultra-high-power fast recovery rectifier bridge stacks and low ESR large-capacity filter electrolytic capacitors.
4. Heat dissipation components: Ultra-large area extruded aluminum alloy heat sink installed on the back of the module, connected to ultra-high-power switching power tubes and rectifier bridge stacks through high thermal conductivity silicone pads; dense strip heat dissipation ribs distributed on left and right side panels to maximize natural convection heat dissipation efficiency without auxiliary cooling fan, zero mechanical wearing parts.
5. Backplane contact components: Large-capacity spring contact connector with 0.35μm thick gold plating on contact surface, effectively preventing long-term plug-in contact oxidation and stabilizing high-current transmission contact resistance.
6. Internal insulation components: Thick mica insulation sheets separating AC high-voltage input circuit and low-voltage DC output circuit; flame-retardant plastic isolation baffles between two DC output channels to completely avoid cross-channel short-circuit risks caused by internal component breakdown failure.

Working Principle

1. AC input filtering and soft-start stage: External industrial AC mains power enters the PW702 module’s three-stage high-efficiency EMI filter circuit first to filter severe grid electromagnetic interference noise generated by large industrial plant high-power equipment. The filtered AC voltage passes through the built-in high-power soft-start charging circuit to limit large power-on surge current, then converted into high-voltage DC through full-wave rectifier bridge and primary side large-capacity filter capacitor group for voltage smoothing treatment.
2. High-frequency switching energy conversion stage: The smoothed high-voltage DC power supply drives ultra-high-power high-frequency switching power tubes to perform PWM pulse width modulation switching action controlled by multi-channel dedicated high-power power management chip. The high-frequency pulse energy generated by high-current switching action is transmitted to each secondary winding coil of the large-capacity isolation transformer through electromagnetic induction coupling.
3. Dual-channel DC voltage stabilization output stage: Each secondary winding coil corresponds to an independent high-current rectification, filtering and precision voltage stabilization circuit. The alternating pulse voltage induced by secondary winding is converted into smooth stable DC voltage through ultra-high-power fast recovery rectifier bridge stack and low ESR large-capacity filter electrolytic capacitor group. The built-in high-precision voltage sampling feedback circuit collects real-time output voltage value of each channel and feeds it back to the primary side PWM control chip to adjust switching pulse duty cycle in real time, realizing constant stable DC voltage output under wide-range variable load conditions of large DCS rack high-density I/O modules.
4. Redundant module synchronous load-sharing control stage: When two PW702 modules are installed in parallel redundant mode in the same large DCS rack, the redundant synchronous communication circuit on the backplane connector transmits real-time load current data between two modules, the built-in load-sharing control chip automatically distributes rack total power supply load evenly to two modules to realize 50% load sharing operation state; when one module suffers fault shutdown, the synchronous communication circuit transmits fault signal to the other standby module instantly, the standby module automatically adjusts internal PWM control logic to increase total output power to bear 100% full rack load within 2ms without power supply interruption.
5. Real-time multi-dimensional fault monitoring and protection execution stage: Multi-channel sampling circuits continuously monitor AC input voltage, each channel DC output voltage, each channel real-time output load current and module internal operating temperature. When any abnormal threshold is triggered, the corresponding hardware protection circuit instantly locks the PWM driving signal of all ultra-high-power switching power tubes to cut off energy transmission of the isolation transformer. At the same time, the module front panel corresponding fault LED indicator lights up synchronously, 3-digit digital display window shows specific fault code information; meanwhile, fault state signal and fault code data are transmitted to DCS rack backplane bus, uploaded to upper-level CENTUM VP operation monitoring screen to display detailed fault information and trigger system multi-level sound and light alarm reminder for maintenance personnel rapid fault location and troubleshooting.

Application Scenarios

• Large-scale petrochemical ethylene cracking device, oil refining atmospheric and vacuum distillation unit CENTUM VP DCS main control cabinet redundant power supply
• Large thermal power plant main boiler, steam turbine, circulating water treatment system high-density DCS rack dedicated redundant power supply module
• Large-scale natural gas liquefaction plant, long-distance oil and gas pipeline central control room large DCS rack redundant power supply equipment
• Nuclear power plant auxiliary facility radioactive waste treatment, circulating cooling water process DCS control cabinet high-reliability redundant power supply

Installation Requirements

1. Large-scale CENTUM VP DCS rack wide power card slot installation operation: Align the wide bilateral guide rails of PW702 with the reserved wide standard power supply slot guide rails inside the large high-density CENTUM VP rack, push the module horizontally inward slowly until the large-capacity backplane connector is fully locked and closely contacted with the rack backplane, then clockwise tighten two side fixing screws with torque controlled at 0.8N·m to prevent module sliding out of the wide card slot under long-term equipment operation vibration.
2. Dual-module redundant parallel installation standard: For high-reliability continuous production process control systems requiring zero power interruption redundant power supply configuration, install two PW702 modules in two adjacent wide power supply card slots of the same large DCS rack, connect the AC input terminals of two modules to the same group of industrial AC mains bus, ensure the backplane redundant synchronous communication pins of two modules are fully contacted with rack backplane bus to realize normal load-sharing redundant operation function.
3. AC input wiring specification: Copper wires with cross-section not less than 1.5mm² must be used for AC input live wire and neutral wire to bear maximum 220VA full-load input apparent power without excessive voltage drop and heat generation; wire stripping length strictly controlled at 8mm to avoid exposed copper strands causing short circuit between adjacent live wire, neutral wire and protective ground terminals; connect the module dedicated protective ground terminal to control cabinet main protective ground bar with copper ground wire cross-section not less than 4mm², single-point reliable grounding to eliminate electrostatic accumulation and leakage electric shock hazard.
4. Cabinet environmental installation conditions: Install the DCS rack equipped with PW702 modules in closed constant temperature air-conditioned electrical control rooms, maintain indoor ambient temperature stable at 18–26℃, avoid direct sunlight, water splashing, corrosive chemical gas and conductive metal dust accumulation around the module; maintain at least 40mm vertical ventilation gap between PW702 power supply module and adjacent I/O modules in the rack, do not block the left and right side panel strip heat dissipation ribs with internal wiring harnesses or plastic cable ties to ensure unobstructed natural convection heat dissipation channel.