DO821
ABB
Overview
The DO821 is a Digital Output from ABB. It provides 8 channels and is built for signal interfacing within the ABB product portfolio systems.
Application & Technical Notes
As a digital output, the DO821 is intended for deployment in panel-based control cabinets and machine enclosures where the ABB product portfolio equipment is installed. It drives actuators, relays, valves and indicators from controller commands, acting as the actuation layer between logic and the machine.
Key published characteristics include 8 channels. These values should be confirmed against the current manufacturer datasheet before final selection, as options and suffixes vary by configuration.
Maintenance & Diagnostics
Avoid condensation — the rated humidity is 5 to 95 %, non-condensing; store and operate the module in a dry, pollution-degree-appropriate enclosure. Verify field wiring, shielding and grounding at installation; check terminal torque and confirm signal types match the configured range. Periodically inspect for loose terminations, induced noise and channel-level diagnostics reported by the controller. Always de-energise the circuit and follow lock-out/tag-out before handling; refer to the official instruction bulletin for service procedures.
Sourcing & Procurement
When sourcing the DO821, distinguish three supply tiers: (1) genuine ABB stock from an authorised distributor; (2) compatible equivalents or surplus/NOS (new-old-stock) from third parties; (3) alternative parts offering equivalent function. Genuine supply carries the full warranty and traceability; compatible or alternative items may be cheaper but should be validated for form, fit, firmware and certification before use in a live system. PLCXpert publishes this page as an independent reference and does not sell the part — verify every claim with the manufacturer or your distributor.
Confirm the module matches your ABB product portfolio rack, the required channel count, signal type and voltage, and the firmware/configuration of the controller. Lead times and pricing vary by region and lifecycle status; obtain a current quote from an authorised channel rather than relying on stale listings.
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Frequently Asked Questions
What is the DO821?
The DO821 is a digital output from ABB. It is described by the manufacturer as: Digital Output.
What are the key technical ratings of the DO821?
Its published highlights include 8 channels. Full electrical, mechanical and environmental limits are listed in the manufacturer datasheet and should be confirmed for your exact suffix.
How is the DO821 mounted or installed?
Installation follows the standard ABB product portfolio mounting practice for this device class; refer to the installation manual for exact dimensions and torque.
Is the DO821 compatible with my controller?
It belongs to ABB's automation product portfolio. Confirm the specific rack, firmware revision, slot rules and configuration with the controller documentation before purchase, as compatibility depends on the exact system build.
What should I check before buying the DO821?
Verify the genuine part number and suffix, confirm it matches your platform and ratings, check the current lifecycle/availability status, and buy from an authorised distributor. PLCXpert provides this reference only and does not sell the component.
Specifications
The DO821 is an 8 channel 230 V a.c./d.c. relay (NC) output module for the S800 I/O. The maximum output voltage is 250 V a.c. and the maximum continuous output current is 3 A. All outputs are individually isolated. Each output channel consists of optical isolation barrier, output state indication LED, relay driver, relay and EMC protection components. The relay supply voltage supervision, derived from the 24 V distributed on the ModuleBus, gives an error signal if the voltage disappears, and the Warning LED turns on. The error signal can be read via the ModuleBus. This supervision can be enabled/disabled with a parameter.
Dimensions
| Note | Width 45 mm (1.77”) Depth 102 mm (4.01”), 111 mm (4.37”) including connector Height 119 mm (4.7”) Weight 0.23 kg (0.5 lbs.) |
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Reproduced from the manufacturer's published data. Values marked "Not available" are absent from the source document.