ABB CHBX01L 2VAA008574R1 Table Description：CHBX01L, Left‑Side Compact Bus Extender, 2VAA008574R1

General Information

Electrical & Interface Specifications

• Backplane Interface: Redundant HN800 I/O bus connectors (A‑bus / B‑bus), high‑speed 4 MBit/s redundant I/O communication bus for SD‑series I/O modulesABB Abilit….
• Power Interface: 24 VDC power input terminals for supplying the entire horizontal I/O row.
• Mechanical Bus Interface: Internal row‑bus connector, cascades power and HN800 bus signals sequentially to every I/O module in the row.
• Signal Type: Redundant HN800 differential bus signals, 24 VDC module supply power distribution.
• On‑Board Circuitry: Bus termination circuitry, power distribution circuit, status LED indicators. No process I/O channels for field sensors/actuators.
• Bus Performance: HN800 bus baud rate 4 Mbit/s, dual redundant A/B bus for fault‑tolerant communicationABB Abilit….
• Power Consumption: Typical 2‑3 W (itself); distributes total row power for all I/O modules on this horizontal segment.
• Operation Limitation: Cannot operate standalone. Must be deployed together with CHBX01R, SD‑series I/O modules and Symphony Plus controller; defines the physical boundary of one horizontal I/O row segment.
• Compatibility Matrix

  ‑ Compatible System: ABB Symphony Plus SD‑Series DCS, HN800 redundant I/O bus system

  ‑ Matching Part: CHBX01R (Right‑side compact bus extender)

  ‑ Compatible I/O modules: All SD‑series SD I/O modules

  ‑ Hot‑swap: Not supported; power‑down the I/O row before replacement.

Environmental Specifications

Main Functions

1. CHBX01L (2VAA008574R1) is the left‑side compact horizontal bus extender for ABB Symphony Plus SD‑Series HN800 redundant I/O bus. It is mounted at left end of a horizontal I/O row, working together with CHBX01R at right‑end to define one complete I/O bus segment.
2. Provides physical termination for dual redundant HN800 A/B I/O bus, distributes 24 VDC auxiliary power supply to all I/O modules along this horizontal row via internal row‑backplane.
3. Realizes high‑speed redundant HN800 bus communication between Symphony Plus controller and SD‑series field I/O modules; dual‑bus design improves communication reliability for critical power‑plant and process‑control applicationsABB Abilit….
4. LED status indicators show power supply status and HN800 bus operating condition for on‑site inspection.
5. No analog / digital field I/O channels; it is purely bus‑power distribution hardware, does not directly connect to field transmitters or actuators.
6. Typical field failure symptoms

   ‑ Entire horizontal I/O row loss of power supply

   ‑ All modules on this row report HN800 bus communication fault

   ‑ Redundant bus single‑channel failure alarm

   Common root causes: 24 VDC input power abnormality, backplane connector poor contact, bus termination hardware damage.

Typical Applications

1. New‑project configuration and spare‑part replacement for Symphony Plus SD‑series HN800 I/O station left‑side bus extender.
2. Power‑plant, pulp‑paper, chemical process DCS control cabinet I/O rack assembly.
3. Preventive‑maintenance spare‑part inventory for ABB Symphony Plus DCS system.
4. DCS system retrofit and expansion of SD‑series I/O stations.