What it handles — encoder types and signal lines
The VW3AP3420 is a digital encoder interface module in the Altivar drive family, designed to connect incremental (A/B/I) and absolute (SSI, EnDat 2.2) encoders to the drive control board. It accepts EnDat 2.2 bidirectional data (Data+/Data-, Clock+/Clock-), SSI clock/data lines, and standard quadrature A+/A-, B+/B-, I+/I- plus temperature sensor inputs (Temp+/Temp-). One female high-density SUB-D 15 connector carries all signals. Maximum operating frequency is 1000 kHz, so it handles high-resolution encoder feedback for precision speed or position loops on servo and closed-loop induction motors.
Supply voltage and current draw
The module is powered from the encoder supply, not the drive backplane — three voltage ranges are supported: 5 VDC (4.75–5.25 V limits), 12 VDC (11.4–12.6 V), and 24 VDC (22.8–25.2 V). Maximum current draw is 0.25 A at 5 V, 0.1 A at 12 V, and 0.05 A at 24 V. The 121 Ω input impedance is fixed for the differential line receivers. Overload and short-circuit protection are built into the interface, so a faulted encoder cable won't take out the drive's encoder supply channel.
Cable distance limits by protocol
Maximum cable length between the encoder and the module depends on the protocol and speed: 100 m for A/B/I incremental, 100 m for EnDat 2.2 with propagation delay compensation enabled, 100 m for SSI at 300 kHz, or 50 m for SSI at full speed and 50 m for EnDat 2.2 without compensation. The 1000 kHz limit applies to the A/B/I incremental channel.
Sourcing note — not a standalone part
Lifecycle status is active per Schneider's current listing — the module is still in regular production. One important procurement constraint: the VW3AP3420 cannot be ordered alone; it is only available in combination with a standard Altivar enclosure (i.e. as part of a drive order or as a field-installed option kit bundled with the drive).