Driver board A16B-1200-0800 A16B-12OO-O8OO A16B12000800

A16B-1200-0800 | FANUC S-Series Twin Digital Servo Control PCB — Dual Axis / PWM / A06B-6058 / 0-B / 0-C / Series 15

S-Series Servo Drives — The CNC Generation This Board Served

The FANUC S-series AC servo amplifiers (A06B-6058 series) represent the second generation of FANUC digital AC servo drives — released alongside the first digital CNC systems of the late 1980s. These drives replaced the earlier analogue servo and servo amplifier generation, bringing digital PWM control to machine tool axes.

The A16B-1200-0800 is the top control card for the twin-axis S-series drives. It sits atop the drive unit as the uppermost PCB — the processing and control intelligence layer over the power stage below. When the CNC sends axis commands to the A06B-6058 drive, the A16B-1200-0800 receives them, processes them, and generates the PWM gate drive signals that command the power transistors in the drive's power section.

Key Specifications

Digital PWM — How the Board Commands the Drives

In digital PWM servo control, the A16B-1200-0800 calculates the required motor current for each axis from the position and velocity error between commanded and actual axis position. It translates this current command into a PWM duty cycle — the ratio of on-time to off-time in the transistor switching cycle — that the drive's power transistors execute at high frequency.

The result is a motor current whose average value closely follows the commanded reference. The higher the PWM switching frequency, the smoother the motor current and the lower the torque ripple on the axis. This digital PWM approach replaced the older analogue current reference approach, giving more consistent axis response across varying load and temperature conditions.

Application Scenarios

S-series drive axis alarm: A machining centre with A06B-6058-H222 twin-axis drives develops a dual-axis servo alarm. After confirming the power section and motor cables are intact, the A16B-1200-0800 control card is identified as the fault. Jumper settings are noted from the failed board, fitted to the replacement, and the drive returns to normal service.

0-C CNC servo drive maintenance: An older 0-C control system running S-series drives has its A16B-1200-0800 control card replaced during a planned servo drive overhaul.

FAQ

Q1: What is the difference between the A16B-1200-0800 and other A16B-1200 series boards?

The A16B-1200 series covers various S-series servo control boards across different drive configurations and motor sizes. The 0800 variant is the twin-axis card for the medium A06B-6058-H22x drives covering 0S/0S through 20S/20S motor ranges. Other A16B-1200 part numbers serve different S-series drive models or single-axis configurations.

Q2: Can the A16B-1200-0800 be used in S-series drives other than A06B-6058-H22x?

The A16B-1200-0800 is confirmed for A06B-6058-H221 through H224 (twin 6058 drives). Other A06B-6058 variants (different current ratings or single-axis versions) may require different control card variants. Always verify the specific drive model from the drive nameplate and cross-reference with the drive's spare parts list before ordering.

Q3: What happens if the S1 and S2 jumpers are set incorrectly?

Incorrect jumper settings on the A16B-1200-0800 typically manifest as: servo alarms immediately on drive enable; incorrect axis speed or following error behaviour; axis moving at wrong speed; or drive overcurrent alarms under low-load conditions. Always check the replacement card's jumper configuration against the drive's maintenance documentation and the original card's settings before powering the system.

Q4: Is the A16B-1200-0800 compatible with FSSB (Fanuc Servo Serial Bus) CNC systems?

No. The S-series A06B-6058 drives use an older serial interface — not FSSB. FSSB was introduced with the Alpha and Alpha-i series in the i-generation CNC. The A16B-1200-0800 is compatible with CNC systems that use the S-series servo bus interface: 0-B, 0-C, 15-series CNC controls. i-generation CNC systems (16i, 18i, 21i) use FSSB and require Alpha-i or Beta-i series servo drives.

Q5: Does replacing A16B-1200-0800 require CNC servo parameter changes?

Servo parameters (axis gains, motor ID, encoder type) are stored in the CNC's parameter memory. Replacing the A16B-1200-0800 does not alter these parameters. However, the S1 and S2 jumper settings on the replacement board must physically match the motor and drive configuration — these are hardware configuration steps, not CNC parameter changes. After fitting with correct jumpers, confirm servo readiness at low speed before full production.