Product Overview
The ASD-A2-0421-U (ASDA20421U) is a high-precision AC Servo Drive from Delta’s premier ASDA-A2 series, specifically designed for high-end motion control applications requiring superior accuracy and speed. Providing a rated output of 400 W, this drive operates on a 220 V single-phase power supply. The "U" type model is a high-performance variant that supports Analog Voltage Control and Pulse Train Input, but is specifically distinguished by its extended support for the E-CAM (Electronic Cam) function and full-closed loop control. It is a critical component for compact, high-speed machinery such as electronic component assembly, semiconductor wafer handling, and precision medical packaging equipment where sub-micron accuracy is a baseline requirement.
Technical Configuration
The ASD-A2-0421-U hardware architecture is centered on a high-speed digital signal processor that handles a 20-bit resolution feedback system (1,280,000 pulses/rev). This "U" model excels in complex motion trajectories thanks to its built-in E-CAM, which allows for the creation of 720-point cam profiles for rotary shears or flying cut-offs. Furthermore, it features a dedicated interface for a second encoder, enabling Full-Closed Loop Control. This allows the drive to read position data directly from the machine's linear scale or external encoder, automatically compensating for mechanical backlash, thermal expansion, or belt stretch. The drive also includes integrated vibration suppression filters to stabilize the system when high-gain settings are used for rapid response.
Technical Specifications
| Attribute |
Specification Details |
| Model |
ASD-A2-0421-U |
| Brand |
DELTA |
| Series |
ASDA-A2 Series |
| Rated Output Power |
400 W |
| Input Voltage |
200 to 230 VAC, 1-Phase |
| Model Type |
U (Extension Port for Full-Closed Loop) |
| Encoder Feedback |
20-bit (1,280,000 p/rev) |
| Control Mode |
Position / Speed / Torque |
| Communication |
RS-232 / RS-485 (Modbus) |
| Pulse Input |
Up to 4 Mbps (Line Driver) |
| Analog Input |
-10 V to +10 V |
| Dimensions |
60 mm x 162 mm x 156 mm |
| Weight |
1.5 kg |
| Shipping Weight |
3.0 kg |
Technical FAQs
What is the benefit of the "Full-Closed Loop" support in the U-type model?
In standard servo systems, the encoder is on the motor, so the drive "thinks" the load is in position even if the coupling or belt has slipped. The ASD-A2-0421-U can connect to a linear scale on the actual machine slide. If there is a 0.05 mm error due to mechanical play, the drive will detect it via the second encoder and correct the motor position to ensure the actual load reaches the exact target.
How does the E-CAM function work within this drive?
The E-CAM allows the drive to simulate a mechanical cam's movement through software. Instead of using complex PLC code to calculate synchronized positions every millisecond, you download a cam table to the drive. The drive then follows a master signal (from a pulse or another motor) and executes the curve internally, providing much smoother motion and faster response than network-based control.
Is this drive compatible with motors from the ASDA-B2 series?
While the drive can physically run many ECMA series motors, it is optimized for the A2 series motors to utilize the 20-bit encoder feedback. Using it with lower-resolution motors may limit the drive's ability to use its advanced vibration suppression and high-gain features effectively.
Engineering & Installation Guide
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Second Encoder Wiring: When implementing full-closed loop control, ensure the external scale or encoder signal is shielded and separated from the motor power cables. Use the CN6 port for the second encoder input. If the signal is unstable, verify that the differential signal (A, /A, B, /B) is used to maintain high noise immunity.
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Pulse Input Signal: For high-speed positioning, use a Line Driver output from your controller to the drive’s CN1 interface. This allows for pulse frequencies up to 4 MHz, which is necessary to take full advantage of the motor's 20-bit resolution without sacrificing speed.
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Heat Dissipation: The 400 W drive is compact (60 mm wide). When mounting multiple units in a row, allow at least 10 mm of horizontal space between drives or use a cooling fan to prevent "Overheat" (AL006) faults, especially if the drives are operating at high duty cycles in a 45 Celsius environment.