The SB822 is a DIN-rail mounted rechargeable external battery unit specifically designed by ABB for its flagship industrial controller platform, the AC 800M series. This product belongs to ABB's Compact Product Suite hardware selector range. Its core function is to provide extended memory backup power for AC 800M controllers, ensuring that critical internal data (such as system parameters, real-time clock, application programs, and runtime data) is not lost during external main power failures or interruptions. This safeguards the continuity and stability of the control system.
In industrial automation and control systems, especially in process control, Distributed Control Systems (DCS), and High Integrity (HI) safety applications, controller reliability and data security are paramount. Brief power fluctuations or unplanned outages can lead to loss of critical process data, controller resets, and even production stoppages or safety risks. As a dedicated external backup power solution, the SB822 effectively compensates for the limited capacity of the AC 800M controller's internal battery, providing longer data retention times. It is a key auxiliary hardware component for building highly available and reliable automation control nodes.
The SB822 is not merely a simple battery holder; it is a complete unit integrating a rechargeable lithium-ion battery pack, power management circuitry, status indication, and protection mechanisms. It seamlessly integrates with the controller's processor unit (PM8xx series) via a dedicated connection cable (TK821V020).
2. Key Functions and Core Features
2.1 Extended Memory Backup Time
Core Value: The primary task of the SB822 is to extend the data retention time of the AC 800M controller after loss of main power. Compared to relying solely on the internal battery of the processor unit (PM851/PM856/PM860/PM861/PM864/PM865/PM866) or a non-rechargeable external battery (SB821), the SB822 provides higher capacity, rechargeable energy storage.
Application Scenario: Suitable for scenarios requiring extended power-off maintenance, power source switching, or environments with unstable power supplies, ensuring controller memory contents are preserved for hours or even days.
2.2 Rechargeable Lithium-Ion Battery Technology
Battery Specification: The unit integrates a prismatic rechargeable lithium-ion battery pack with a nominal voltage of 3.75V and a capacity of 2.3 Ah. The lithium metal equivalent content is 0.8 grams.
Reusability: The battery can be recharged via connection to the controller's 24V DC supply, enabling cyclic use. This reduces the frequency and cost of consumable replacement over long-term operation, aligning with modern industrial sustainability requirements.
Independent Charge Management: The SB822 unit incorporates built-in charge management circuitry. When connected to 24V power and with the controller's main power normal, it automatically charges and maintains the internal battery.
2.3 Status Monitoring and Indication
The SB822 is designed with clear status indicators for quick diagnostics by field maintenance personnel:
Green Power LED: Indicates that the 24V DC input power is normal.
Yellow Charge LED: Indicates that the battery is charging or in a charged state.
The B(attery) LED indicator on the controller's processor unit (PM8xx) panel will flash, signaling that the memory backup function is active and powered by the external battery (SB822). The combination of indicators on both units provides dual visual feedback on system power health.
2.4 Plug-and-Play and Easy Installation
DIN-Rail Mounting: Features standard DIN-rail (35 mm) mounting, allowing flexible and secure installation within the controller cabinet, saving space.
Dedicated Connection Cable: Includes a dedicated 2-meter long connection cable TK821V020. One end connects to the SB822 unit, the other to the "External Battery Supply Socket" on the PM8xx processor unit. Connection is simple and reliable.
Included Connectors: The packaging includes a connector for the 24V power supply, facilitating field wiring.
2.5 High-Reliability Design
Protection Rating: Housing protection rating is IP20 (according to IEC 60529 / EN60529), preventing ingress of solid objects larger than 12.5mm diameter, suitable for internal industrial control cabinet environments.
Environmental Compatibility: Operating ambient temperature range is 0 to +55 °C, meeting the temperature conditions of most industrial sites.
Safety Certifications: The product complies with CE marking requirements and meets RoHS (DIRECTIVE/2011/65/EU) and WEEE (DIRECTIVE/2012/19/EU) directives, conforming to EU environmental standards for hazardous substance restrictions and waste electrical and electronic equipment recycling.
Corrosion Resistance: Suitable for corrosive atmospheres classified as ISA-71.04 G2 (Moderate).
Pollution Degree: Complies with IEC 60664-1 Pollution Degree 2, suitable for general industrial environments.
2.6 Redundant System Support
When the AC 800M controller is configured for redundant CPU operation (e.g., using PM861/PM864/PM865/PM891 as a redundant pair), to ensure both processor units have independent and reliable backup power, two SB822 units are required, one connected to each the primary and backup CPU.
3. Installation, Connection, and Operational Guidelines
The installation and connection of the SB822 must adhere to a specific procedure to ensure safety and proper functionality:
Unpacking and Battery Activation:
Mechanical Installation:
Power Connection:
Using the connector enclosed in the packing box, connect the 24V DC supply to the terminals marked "24V" (X3) on the SB822 unit. This power supply, used for charging the battery, should come from a reliable circuit.
Controller Power-Up:
Battery Unit Connection (Critical Step):
Important Note: Before connecting the TK821V020 cable, you must confirm that the AC 800M controller is powered up normally and that the B(attery) LED indicator on the front panel of the PM8xx processor unit has started flashing. This indicates the controller's memory backup function is active.
Plug one end of the TK821V020 cable into the SB822 unit and the other end into the "External Battery Supply Socket" on the PM8xx processor unit (refer to Figure 2 in the hardware manual).
Warning: If the PM8xx processor unit is not connected to the main power supply, connecting the TK821V020 cable at this point will cause the CPU memory to immediately start consuming battery power, potentially depleting the battery accidentally during installation.
Status Verification:
Redundant System Configuration:
For redundant CPU configurations (e.g., dual PM861/PM864/PM865/PM891), two SB822 units are required, each connected to its corresponding primary or backup processor unit using a TK821V020 cable.
Internal Battery Handling (Important):
When using the SB822 external battery unit, the internal battery inside the PM8xx processor unit must be removed. This is because having two batteries in parallel can affect the system's monitoring of battery status (the system monitors only one battery) and may reduce the actual available backup time due to mismatches. The manual explicitly states: "status monitoring is only provided for one battery."
4. Maintenance and Troubleshooting
4.1 Regular Maintenance
Regular Charging: To keep the battery in optimal condition, regular maintenance charging of the SB822 via the connected 24V power supply is recommended, even if no power outage has occurred. The manual advises "charge it on a regular basis to prevent problems."
Status Monitoring: Maintenance personnel should regularly observe the indicator lights on the SB822 and the B LED status on the controller.
4.2 Battery Replacement
When battery performance degrades or reaches its end of life, the internal lithium-ion battery pack must be replaced. The replacement procedure strictly follows ESD (Electrostatic Discharge) protection and safe operation practices:
Disconnect the TK821V020 cable and the 24V power supply cable.
Remove the SB822 unit from the DIN-rail.
The operator must wear a properly grounded ESD wrist strap.
Carefully open the SB822 unit's cover and locate the battery pack.
Carefully disconnect the battery connector from the Printed Circuit Board (PCB).
Remove the old battery pack.
Insert the new battery pack and connect it.
Reassemble the unit in reverse order and reinstall it on the rail.
Dispose of the worn battery pack in an approved manner according to local regulations.
4.3 Common Faults and Handling
| Fault Symptom | Possible Cause and Corrective Action (for SB822) |
|---|
| B(attery) LED indicator on PM8xx processor unit is flashing (This is the normal operating state indicator, but requires checking if it flashes when no external battery is used or if the state is abnormal.) | 1. Check external battery connections: Ensure both ends of the TK821V020 cable are secure.
2. Check SB822 indicators: If the Charge LED and/or Power LED on the SB822 are turned off:
a. Check 24V power supply connections: Ensure the 24V charging power is properly connected to the SB822.
3. If condition persists:
b. Renew the lithium-ion battery pack (see replacement steps above). |
| The system time is incorrect following a power failure | Renew the external battery (The SB822 battery may no longer be able to maintain power for the Real-Time Clock (RTC)). |
5. Application and Compatibility within the AC 800M System
The SB822 is an integral part of the AC 800M controller hardware ecosystem:
Wide Compatibility: Supports all PM8xx series processor units requiring extended backup time via an external battery, including PM851, PM856, PM860, PM861, PM864, PM865, PM866. Special Note: For the PM891 processor unit, which does not contain an internal battery, the SB822 is a mandatory option for providing any memory backup functionality.
Integration with High Integrity (HI) Systems: The AC 800M High Integrity controller (based on PM865+SM810/SM811) can be used in safety-critical applications (SIL2/SIL3). While the SB822 itself is not a safety-certified component, it provides the foundational power security for the data integrity of the entire high-integrity controller, serving as crucial support for reliable system operation.
System Integration Example: Diagrams in the hardware manual (e.g., Figures 12, 13) show I/O interconnection schemes in single-controller configurations including PM891 and SB822, with the SB822 integrated as the "last line of power defense" for controller data security.
6. Safety and Usage Precautions
Installation Sequence: Always adhere to the sequence: "Power up the controller first, wait for the B LED to flash, then connect the SB822 cable" to prevent the battery from being drained during installation.
Battery Parallel Connection Prohibition: When using the SB822, the internal battery in the PM8xx processor must be removed to avoid parallel usage.
Electrical Safety: Follow all relevant electrical safety regulations before installation, wiring, and maintenance; disconnect power if necessary.
Electrostatic Discharge Protection: Effective ESD protection measures must be taken when replacing the battery to avoid damaging sensitive electronic components.
Environmental Requirements: Ensure the SB822 is installed in an environment meeting its protection rating (IP20) and temperature range. Avoid exposure to water, oil, or extreme temperatures.
Battery Disposal: Discarded lithium-ion batteries are special waste and must be recycled according to local environmental regulations and professional guidelines; they must not be disposed of casually.
Regular Inspection: Incorporate SB822 status checks into the control system's regular preventive maintenance schedule.
