ABB SACO64D4 4-Pole Digital Annunciator
The ABB SACO64D4 is a self-contained microprocessor-based digital annunciator unit with 64 independent alarm channels. This device is used in applications requiring supervision of alarm and signaling contacts in power plants, substations and industrial process installations. The annunciator provides immediate fault identification, visual and audible alerts during abnormal process conditions, and subsequent means for fault analysis.
Technical Specifications
The SACO64D4 is a standalone microprocessor-based annunciator unit that can operate independently or as part of a larger system. The maximum system capacity when multiple units are interconnected is 560 channels, with time stamping resolution of 10 milliseconds for accurate event sequence recording. The unit features 16 output relays, with 14 dedicated for group real-time alarming, one for audible device control and one for self-monitoring of system health.
The device is approved for offshore installations and marine applications, demonstrating suitability for demanding environments with high electrical and electromagnetic interference. The annunciator can be used as a standalone unit or multiple units can be interconnected and connected to printers, terminals and other devices to form complete supervision, sequence-of-events reporting and data acquisition systems.

Microprocessor-Based Design
The microprocessor-based design of the SACO64D4 provides significant advantages over conventional electromechanical annunciators. Conventional annunciators have fixed wiring and manual setting of alarm parameters, while the SACO64D4 is programmable, allowing characteristics and behavior to be configured for each channel without hardware changes. The annunciator is also multifunctional, with programmable alarm sequences that can be selected and configured to match specific application requirements.
The self-checking facility continuously monitors the health of the device, providing early warning of any internal failures. The low burden of the digital inputs improves measurement accuracy and reduces loading on monitored circuits. Fast fiber optic communication capability allows connection to substation LANs and remote monitoring systems. The device permits storage of historical data with time stamps, enabling post-event analysis and troubleshooting.
Alarm and Display Functions
The SACO64D4 provides immediate visual and audible indication when an alarm condition occurs. Each of the 64 alarm channels has dedicated indication on the front panel, allowing operators to quickly identify the source of an alarm. Programmable alarm sequences determine how the annunciator responds to incoming alarms, including latching or non-latching operation, automatic reset or manual acknowledgment, and first-out indication to identify the initial alarm in a cascade of events.
The device can also be used as a central alarm panel in control rooms, providing consolidated alarming from multiple field locations. The event reporting function records the sequence of alarms with precise time stamps, enabling operators to understand the progression of events leading to abnormal conditions and take appropriate corrective actions.
Applications
The ABB SACO64D4 is deployed across a wide range of alarm monitoring applications. Power plants use the annunciator for turbine and boiler alarm supervision, generator protection alarming and auxiliary system status monitoring. Substations employ the device for breaker and transformer alarm indication, protection relay event annunciation and DC system monitoring. Industrial process installations use the annunciator for monitoring critical process parameters, equipment status and safety system contacts. Offshore platforms rely on the device for fire and gas alarm annunciation, emergency shutdown system monitoring and marine systems supervision.


