Control Board A20B-2101-0051 A2OB-21O1-OO51 A20B21010051

A20B-2101-0051 | FANUC Beta-i SVM1-80i / SVM1-40HVi Servo Control PCB — FSSB / HRV2 & HRV3 / 200V and 400V HV / A06B-6130-H004 / A06B-6131-H003

Beta-i SVM1 — Economy Single-Axis Drive

The FANUC Beta-i series (βi) is FANUC's economy servo drive product line. Where the Alpha-i targets high-performance machining applications, the Beta-i provides reliable servo function for less demanding machines at a lower cost per axis. The SVM1 (Single-axis servo module) within the βi range covers a broad current spectrum:

The A20B-2101-0051 control PCB serves the two highest-rated configurations: the SVM1-80i and the SVM1-40HVi. Both use this same control card.

Key Specifications

A20B-2101-0051 vs A20B-2101-0050 — Why Two Control Cards?

Within the Beta-i SVM1 range, two control cards share the work:

A20B-2101-0050: Control card for smaller SVM1 models — SVM1-4i, SVM1-20i, SVM1-40i (200V variants up to 40A). The lower-current devices need different feedback scaling and gate drive interface parameters.

A20B-2101-0051: Control card for the larger SVM1 models — SVM1-80i and SVM1-40HVi. The higher-current and high-voltage variants require different internal circuit configurations to handle the higher feedback signal levels and gate drive characteristics.

These two cards are not interchangeable — fitting A20B-2101-0050 in a SVM1-80i, or A20B-2101-0051 in a SVM1-4i, results in incorrect servo behaviour or hardware faults.

Application Scenarios

SVM1-80i control card alarm: A FANUC Beta-i SVM1-80i module generates a persistent servo alarm. The power PCB tests correctly. The A20B-2101-0051 control card is identified as the fault. Replacement restores servo axis function.

SVM1-40HVi (High Voltage) repair: A CNC installed in a 400V region uses the A06B-6131-H003 HV servo module. A control card fault is diagnosed. The A20B-2101-0051 (which serves both 200V and HV variants) is the correct replacement card.

FAQ

Q1: Why does the SVM1-40HVi (A06B-6131 series) use the same control card as the SVM1-80i (A06B-6130)?

The control card A20B-2101-0051 manages the digital processing, FSSB communication, and current loop calculation — functions that are independent of the mains input voltage level. The power PCB handles the voltage-specific hardware for 400–480VAC input. Using the same control card for both 200V and HV variants simplifies spare parts stocking — one A20B-2101-0051 serves both applications.

Q2: What is the power PCB paired with A20B-2101-0051 in each module?

• SVM1-80i (A06B-6130-H004): power PCB A16B-3200-0513
• SVM1-40HVi (A06B-6131-H003): power PCB A16B-3200-0517

These power PCBs handle the high-current path. The A20B-2101-0051 control card manages the digital control and feedback processing. Both boards must be present and functional for the module to operate correctly.

Q3: Does replacing A20B-2101-0051 require servo parameter changes in the CNC?

No. Servo motor parameters (motor ID code, encoder type, current limits, loop gains) are stored in the CNC's main parameter memory, not in the Beta-i servo control card. After fitting the replacement A20B-2101-0051, the CNC re-establishes FSSB communication with the module and applies the existing servo parameters. Verify servo readiness and run low-speed tests before resuming full production.

Q4: How does FSSB operation work with the A20B-2101-0051?

The Beta-i SVM1 modules with A20B-2101-0051 use FSSB for CNC-to-drive communication. The fibre optic cable from the CNC's servo card connects to the SVM1's FSSB input. The A20B-2101-0051 processes the incoming optical FSSB data, extracts the position command for its axis, and returns encoder feedback data on the same optical link in the opposite direction. This bidirectional fibre optic communication happens every interpolation cycle.

Q5: Is A20B-2101-0051 limited to FSSB, or does it also support Type-A or Type-B serial interface?

The Beta-i SVM1 modules with A20B-2101-0051 use the FSSB fibre optic interface. Beta-i drives with I/O Link interface (for CNC-controlled axes via I/O Link rather than FSSB) use different module order numbers and different internal boards. The A20B-2101-0051 specifically serves the FSSB-interface SVM1-80i and SVM1-40HVi modules.