DO821 ABB - Relay Output Module | 8-Channel 230V

ABB DO821 Relay Output Module for S800 I/O Systems

The ABB DO821 provides reliable relay output control for industrial automation applications. This 8-channel module handles high voltage loads up to 250V AC/DC with robust 3A contacts. It offers individual channel isolation and comprehensive diagnostic capabilities.

Key Technical Specifications

• Brand: ABB
• Model: DO821
• Output Channels: 8 relay channels
• Voltage Rating: 5-250V AC/DC range
• Current Capacity: 3A per channel continuous
• Contact Type: Normally Closed (NC) configuration
• Isolation: Individual channel-to-channel isolation
• Power Dissipation: 2.9W typical operation

Electrical Characteristics

• Output Type: Relay contacts with NC operation
• Maximum Voltage: 250V AC/DC working voltage
• Dielectric Strength: 2000V AC test voltage
• Current Consumption: 60mA at +5V ModuleBus
• Relay Power: 140mA at +24V ModuleBus
• Cable Length: 600 meters maximum field wiring

Protection and Safety Features

• Individual channel isolation for safety
• EMC protection components on all outputs
• Optical isolation barriers for noise immunity
• Relay power supply voltage monitoring
• Overvoltage Category: III according to standards
• IP20 protection against dust and contact

Environmental Specifications

• Operating Temperature: 0°C to +55°C range
• Storage Temperature: -40°C to +70°C limits
• Humidity Range: 5% to 95% non-condensing
• Pollution Degree: Level 2 classification
• Corrosion Protection: ISA-S71.04 G3 rating
• Vibration Compliance: IEC 61131-2 standard

Diagnostics and Monitoring

• 8 individual channel status LEDs
• Module indicators: Fault, Run, Warning, OSP
• Relay supply voltage supervision
• ModuleBus communication for diagnostics
• Configurable error detection parameters
• Real-time status monitoring capability

Installation and Compatibility

• Compatible with S800 I/O mounting units
• Works with TU811, TU813, TU831 MTUs
• Keying code CA for proper installation
• Compact dimensions: 45mm W × 119mm H × 102mm D
• Weight: 0.23 kg for easy handling
• Standard rail mounting design

Packaging and Shipping

• Includes one ABB DO821 module
• All necessary installation components
• Fast worldwide shipping via FedEx, UPS, DHL
• Secure industrial packaging protection

Frequently Asked Questions

• What does Normally Closed (NC) mean?
  NC contacts are closed when the relay is not energized and open when activated for fail-safe operation.
• How is channel isolation beneficial?
  Individual isolation prevents cross-channel interference and allows mixed voltage applications on different channels.
• What monitoring capabilities are available?
  The module provides relay power monitoring and status indicators with ModuleBus communication for system integration.