ABB SD834 3BSC610067R1 Power Supply

The SD834 is the flagship power module within the ABB AC 800M controller hardware platform and the System 800xA family. It is a high-performance, high-reliability 24V DC power supply with a rated output of 20A/480W. As the highest-power member of the SD83x series, the SD834 is specifically designed to meet the stringent power supply demands of large-scale, high-load, high-availability industrial automation systems. It integrates advanced switched-mode power supply technology, comprehensive protection functions, flexible scalability, and full international safety certifications, making it the ideal power solution for building critical process control systems, redundant power architectures, and High Integrity (HI) applications.

The SD834 serves as the "power core" within the AC 800M system:

• High-Capacity Single System Power: Provides ample power for large single-controller systems equipped with multiple high-performance processor units (e.g., PM865, PM891), numerous CEX-Bus communication interface modules (e.g., CI871 PROFINET IO, CI873 EtherNet/IP), and extensive distributed S800 I/O networks.

• Core Component for Redundant Power Systems: Its parallel capability, combined with SS823/SS832 diode voting units, allows for easy construction of N+1 or N+M redundant power architectures. This provides uninterrupted power security for high-availability systems like the AC 800M High Integrity controller, ensuring seamless power supply during a single supply failure.

• Scalability and Flexibility: Its unique parallel operation capability allows multiple SD834 units to be connected in parallel to deliver a total output power far exceeding that of a single unit, meeting extreme demands of ultra-large cabinets or centralized power distribution.

• Status Monitoring and Diagnostics: The built-in DC-OK relay contact provides remote power status monitoring, facilitating integration into higher-level management systems for early warning and diagnostics.

Core Features and Benefits

1. High Power and Exceptional Efficiency: Delivers continuous output capability up to 20A/480W, sufficient to power the most complex control stations. Peak efficiency exceeding 93% not only significantly reduces operational energy consumption and costs but, more importantly, minimizes heat buildup within the cabinet. This enhances the long-term reliability of the entire system and reduces air conditioning requirements.

2. Flexible Power Scalability (Parallel Operation): This is the signature feature that distinguishes the SD834 from other models in the series. Users can proportionally increase total output current by connecting multiple SD834 units in parallel (e.g., two units for up to 40A). This provides unparalleled flexibility for future system expansion or for meeting the extreme power demands of a single cabinet, without the need to overhaul the power architecture.

3. Advanced Diagnostics and Monitoring (DC-OK Relay): The built-in floating relay contact continuously monitors its own output voltage status. The contact opens when the output voltage falls below 90% of the set value and closes when normal. This signal can be wired to a DI module or PLC, enabling remote real-time alarm for power failure and system status logging. It is a key tool for preventive maintenance and rapid fault localization.

4. High-Reliability Design: Incorporates active Power Factor Correction (PFC) technology to reduce harmonic pollution. Features advanced protection: overvoltage, overcurrent, short-circuit "hiccup" protection (with auto-recovery), and overtemperature protection. Wide-range AC/DC input allows it to adapt to various unstable power grids worldwide.

5. Enhanced Safety Compliance: In addition to meeting basic CE and UL certifications, the SD834 is also certified for Class 1, Division 2 (cULus), allowing its direct use in specific hazardous areas in North American industries such as oil & gas and chemicals, meeting broader market access requirements.

6. Optimized for Redundant Systems: Perfectly matched with SS823/SS832 voting units to build high-availability redundant power supplies. Its stable performance and precise voltage regulation ensure even load sharing among power units in a redundant configuration, enabling smooth, bumpless transfer.

Installation, Configuration, and Wiring Guidelines

Safety Precautions Before Installation

• Strictly follow manual warnings: Read the "Safety Summary" in the AC 800M Controller Hardware manual before operation. Ensure all work is performed with the power completely disconnected.

• Environment and Heat Dissipation: Ensure the installation environment meets specifications and strictly adhere to the minimum mounting clearances of 15mm lateral and 40mm vertical. This is critical for heat dissipation and long-term full-load operation.

• Grounding is Critical: As a Class I device, the Protective Earth (PE) must be connected firmly and with low impedance to the cabinet grounding busbar. This is fundamental for safety and EMC performance.

Mechanical Installation

1. Reserve sufficient space on a sturdy TS 35/7.5 DIN rail.

2. Align the slots on the back of the SD834 with the top edge of the rail, press down, and rotate the module until the bottom latch locks into place.

Electrical Wiring

A. Single Unit Operation Wiring:

1. Input Side: Connect AC (L, N) or DC power to the corresponding terminals, and connect the PE wire. Install a 10-20A MCB upstream.

2. Output Side: Connect the +24V and M outputs to the system power busbar or distributor.

3. DC-OK Relay: Use the Normally Open (NO) and Common (C) contacts of the relay output and connect them to a monitoring system (e.g., DI channel). Note the contact rating (max 60Vdc/0.3A, 30Vdc/1A).

B. Parallel Operation Wiring (Refer to manual Figure 98 and Table 114):

1. Voltage Calibration: Before connecting in parallel, the no-load output voltage of each SD834 unit must be adjusted using a screwdriver to be as consistent as possible (recommended deviation within ±500mV). This is a prerequisite for ensuring proper current sharing and DC-OK signal functionality.

2. Output Connection: Connect the +24V and M outputs of each unit in parallel to a common output busbar.

3. Key Limitations:

• Current Limit: The continuous current through the output terminals of each SD834 should not exceed 25A.

• Quantity & Current Sharing: Generally, it is recommended not to parallel more than 3 units. If more than 3 are used, consider adding a diode in series with the positive output of each unit to prevent circulating currents, but this requires careful evaluation of voltage drop impact.

• DC-OK Signal: In parallel applications, the DC-OK signal from a single unit may not accurately reflect the bus voltage status. Consider comprehensive judgment via external circuitry or direct monitoring of the bus voltage.

C. Redundant Configuration Wiring (via SS823/SS832):

1. Each SD834 serves as an independent power source. Its output is connected to the corresponding input of the SS823/SS832 voting unit.

2. The output of the voting unit (+24V, M) is connected to the load system.

3. Important Warning (from manual): In AC 800M High Integrity controllers, the redundant power supply configuration must strictly follow the standard diagrams. It is not permitted to arbitrarily alter the standard configuration by means such as installing individual circuit breakers between modules.

Operation, Maintenance, and Troubleshooting

Power-up and Status Verification

• After power-up, the green output LED should illuminate.

• Measure the output voltage; it should be around 24V (adjustable if needed).

• Verify the DC-OK relay: its contacts should be closed (conducting) when the output is normal.

Preventive Maintenance

• Periodically clean dust from ventilation slots.

• Check and tighten input/output terminals.

• In redundant systems, periodically test by taking one power supply offline to verify the voting unit's切换 function.

Common Faults and Handling

• No Output, LED Off: Check input power, upstream circuit breaker/fuse.

• Output LED Flashing or Off: Could indicate overload, short circuit, or overtemperature protection. Check the load, verify heat dissipation conditions, wait for auto-recovery in "hiccup" mode, or restart after cooling.

• DC-OK Signal Abnormal: Check relay wiring; in parallel applications, check output voltage consistency.

• Uneven Current Sharing in Parallel System: Recalibrate the no-load output voltage of all modules to be consistent.

Safety Warning: Do not disassemble the module unless you are a qualified professional. For complex faults, contact qualified technical personnel.

Application Scenarios

• Large Process Control Systems (DCS): Main control stations in refineries, chemicals, power generation, driving numerous controllers and I/Os.

• High Availability & High Integrity (HI) Systems: As the core of redundant power supplies for Safety Instrumented Systems (SIS).

• Factory Automation Central Cabinets: Centralized power for main PLCs, drive networks, and remote I/O heads for multiple production lines.

• Infrastructure & Energy: Large water treatment plants, substation automation, data center environmental control.

• Equipment for Class 1 Div 2 Hazardous Areas: Facilities in the oil & gas sector meeting relevant North American standards.

Comparison with Other Models in the SD83x Series

Table 2: SD83x Series Power Module Selection Guide