Description
The SERVOSTAR 406A-C is a high-performance, compact digital servo amplifier from the legacy SERVOSTAR 400 series. It was designed to provide precise control for brushless AC servo motors in a “book-style” form factor that saves significant space in electrical cabinets.
The “406” designation indicates a 6 Ampere continuous current rating, making it suitable for small to mid-sized axes in automated assembly, medical equipment, and semiconductor manufacturing.
Model Code Breakdown (406A-C)
- 406: 6 Amps continuous output current (12 Amps peak).
- A: Analog/Basic version (Supports +/- 10V velocity or torque commands).
- -C: CANopen communication interface is integrated on-board for digital networking.
Technical Specifications
The 406A-C utilizes a 230V AC input to provide high-bandwidth control of motor torque, speed, and position.
| Parameter | Specification |
| Continuous Current | 6 A |
| Peak Current (5s) | 12 A |
| Input Voltage | 1 x 230V AC or 3 x 230V AC (50/60 Hz) |
| Feedback Types | Resolver (Standard), Encoder, or ComCoder |
| Communication | CANopen (DS301/DSP402) and RS232 (for setup) |
| Interface | +/- 10 V Analog / Step-Direction / Master-Slave |
| Protection | Short circuit, Overvoltage, Ground fault, Overtemperature |
Core Functionality and System Role
The SERVOSTAR 400 series was among the first to bring fully digital, high-speed processing to a drive of this size.
1. Integrated Motion Control
While primarily an amplifier, the 406A-C features an internal position controller. When used via the CANopen interface, the drive can handle complex tasks like Homing, Point-to-Point positioning, and Jogging without requiring a separate high-speed motion controller for every axis.
2. Robust Feedback Options
The drive is natively equipped to handle Resolvers, which are far more durable than optical encoders in high-heat or high-vibration environments. However, it is flexible enough to be configured for incremental encoders if high-resolution precision is required.
3. Fully Digital Control Loops
The drive features a nested control architecture. The current loop is updated at extremely high frequencies (62.5 \mu s), ensuring that motor torque is instantaneous and smooth, which reduces mechanical wear on gearboxes and couplings.
Engineering Insights: Deployment and Maintenance
1. Commissioning via RS232
To set up the SERVOSTAR 406A-C, you must use the DRIVE.EXE or S400/S600 GUI software.
- Best Practice: The connection is made via the X6 port using a null-modem serial cable. If you are using a USB-to-Serial adapter, ensure it uses a high-quality chipset (like FTDI) to prevent data corruption during parameter downloads.
2. Thermal Management and “Zero-Stacking”
The 406A-C is designed for “zero-stacking,” meaning multiple drives can be mounted side-by-side without gaps.
- Constraint: While they can be mounted side-by-side, they rely on vertical airflow. Do not block the vents at the top or bottom of the drive. In 6A models, the heat sink is passive; if your cabinet temperature exceeds 45°C, you must provide forced-air cooling.
3. Common Fault: F04 (Feedback)
The most frequent error code on this unit is F04.
- Troubleshooting: This indicates a feedback fault. Because the drive uses a high-frequency carrier signal for the resolver, check for “crosstalk.” Ensure the feedback cable is shielded and that the shield is grounded at the drive’s front panel using the supplied shielding clamps.
4. The DC Bus and “Reforming”
If a 406A-C has been sitting in a spare parts room for more than two years:
- Critical Warning: Do not apply full 230V power immediately. The internal electrolytic capacitors can fail. Use a variable AC source (Variac) to slowly increase the voltage over 4–8 hours to “reform” the capacitors safely.
FAQ
Q: Can I use this drive on 480V power?
A: No. The SERVOSTAR 400 series is strictly for 230V AC. Applying 480V will destroy the input rectifier and the DC bus capacitors. For 480V, you would need the SERVOSTAR 600 series.
Q: What is the difference between the “A” and “S” models?
A: The “A” is the Analog/CANopen model. The “S” model (e.g., 406S) was a specialized version often used for SERCOS fiber-optic communication, which is not compatible with the hardware in the 406A-C.
Q: Does it support “Safe Torque Off” (STO)?
A: Standard 400 series drives from the early production runs do not have integrated STO. Safety must be handled via external contactors that drop the 230V mains power to the drive.
