ABB SNAT630PAC: Key Interface for Resolver & Encoder Feedback Systems

In a high-precision printing press, a series of ACS880 multidrive units control individual printing cylinders. Perfect color registration requires each cylinder motor to maintain an exact speed and angular position relative to the others, with micron-level synchronization. Each motor is equipped with a high-resolution sine-cosine encoder that outputs delicate analog signals. The ABB SNAT630PAC Pulse Amplifier​ is installed in each drive’s control unit. It receives the raw, low-voltage sine/cosine (1 Vpp) signals from the encoder. The board’s primary function is to amplify, condition, and convert these analog waveforms into clean, digital pulse trains (A, B, and Z channels) and a digital representation of the signals (via an internal interpolator). It also provides the necessary excitation voltage for the encoder. This robust digital signal is then fed to the drive’s main controller board. Without the SNAT630PAC, the sensitive encoder signals would be vulnerable to electrical noise from the powerful motor cables, leading to erroneous position data, “following errors,” and visible misalignment in the print. This board is the unsung hero that enables the extreme precision required in synchronous multi-axis applications.