Product Overview
When a digital output module fails in a critical process, production halts and troubleshooting becomes urgent. The ABB DO818 32-channel digital output module for the S800 I/O system is designed to prevent such disruptions. With 32 channels for 24 V d.c. and two isolated groups, each containing 16 outputs and a voltage supervision input, this module ensures reliable switching even in demanding environments. Its robust protection against short circuits, over voltage, and over temperature minimizes downtime and simplifies maintenance.
Technical Specifications Breakdown
The DO818 delivers a process voltage range of 12-32 V d.c. (nominally 24 V d.c.) and a maximum continuous output current of 0.5 A per channel. The outputs are divided into two individually isolated groups (RIV50V) with 16 channels each, plus one process voltage supervision input per group. This supervision triggers a channel error signal when the process power drops below 12 V, allowing early detection of power issues. The module features groupwise isolation from ground, a rated insulation voltage of 50 V, and a dielectric test voltage of 500 V a.c. Power dissipation is typically 2.8 W, and current consumption on the +5 V ModuleBus is typically 70 mA, with 40 mA on the +24 V external supply. The maximum field cable length is 600 meters (656 yards), supporting flexible installation layouts.
Industry Applications
In manufacturing lines, the DO818 controls solenoid valves, motor starters, and indicator lights. Its two isolated groups allow separate power domains for different machine sections, reducing fault propagation. For example, in a packaging line, one group can handle conveyor actuators while the other manages safety gates. The voltage supervision input alerts operators if the process voltage drops, preventing erratic behavior. This reliability is critical for continuous processes where unplanned stops are costly.
Installation & Setup Guidance
Mount the DO818 onto an S800 I/O base unit or MTU (TU818, TU819, or TU830). Ensure the module is correctly keyed (keying code EA) to prevent insertion into incompatible slots. Connect the process voltage (12-32 V d.c.) to the group inputs, observing polarity. Use shielded cables for field wiring up to 600 meters to maintain signal integrity. The module's IP20 protection requires installation in a clean, dry cabinet. For vertical mounting in compact MTU, derate the maximum ambient temperature to 40 °C (104 °F).
Maintenance & Reliability
From a maintenance engineer's perspective, the DO818 simplifies diagnostics with front panel LEDs for Fault (F), Run (R), Output Status (O), and individual channel status for channels 1-32. The voltage supervision provides early warning of power loss, allowing proactive intervention. The module's protection against short circuits and over temperature reduces the need for fuse replacements or component swaps. Periodic inspection of the process voltage and environmental conditions (0 to +55 °C operating, 5-95% non-condensing humidity) ensures long service life. The corrosion protection rating ISA-S71.04: G3 suits harsh industrial atmospheres.
Compatibility & Integration
The DO818 integrates seamlessly with the ABB S800 I/O system via the ModuleBus. It is compatible with MTUs TU818, TU819, and TU830. The module supports groupwise isolation and works with standard 24 V d.c. field devices. For system integration, verify that the controller supports the S800 I/O series and that the ModuleBus power supply can handle the module's current consumption (70 mA on +5 V, 40 mA on +24 V external).
Selection Guide & Purchasing Advice
Before ordering the DO818 (article number 3BSE069053R1), confirm your system's voltage requirements and channel count. The module provides 32 digital outputs, but each group has 16 channels, so plan your wiring accordingly. Ensure your MTU matches the keying code EA. For replacement or new installations, SpareTechPLC offers the DO818 with fast shipping and expert support. Please verify current lifecycle status and availability with SpareTechPLC before ordering.
Troubleshooting & Common Issues
If an output channel fails to activate, check the process voltage supervision indicator. If the voltage drops below 12 V, the module reports a channel error. Verify the external 24 V d.c. supply and connections. If a group is non-functional, test isolation by measuring resistance between group commons (should be >50 V rated insulation). Overheating may occur if ambient temperature exceeds 55 °C (131 °F) or 40 °C for vertical compact mounting. Ensure adequate airflow and reduce load if necessary. The DO818's diagnostic LEDs help pinpoint issues quickly.
Frequently Asked Questions (FAQs)
Q1: How many outputs does the DO818 have?
A1: The DO818 has 32 digital output channels, divided into two isolated groups of 16 channels each.
Q2: What is the maximum current per channel?
A2: The maximum continuous output current is 0.5 A per channel.
Q3: Can I use the DO818 with a 12 V d.c. supply?
A3: Yes, the process voltage range is 12-32 V d.c., nominally 24 V d.c.
Q4: What does the voltage supervision do?
A4: Each group has a voltage supervision input that generates a channel error signal if the process power drops below 12 V, alerting the system to power issues.
Q5: Is the DO818 compatible with TU830?
A5: Yes, the DO818 is compatible with MTUs TU818, TU819, and TU830.
