We had an enquiry from a customer running a servo motor at high speed who kept getting feedback errors during fast acceleration. Their existing encoder just could not keep up once the motor got moving, and the drive would occasionally lose track of position.
This usually comes down to encoder bandwidth, not the drive itself. Hengstler’s S21 is an optical sinewave, or sin/cos, encoder built for motor feedback, and it holds full signal quality up to a bandwidth of 500 kHz, so it can keep up at peak motor speed instead of becoming the bottleneck. It is rated for a wide operating temperature range of -15°C to +120°C, which matters since it usually sits directly on the motor and picks up heat from it, and it has good immunity to electrical interference, rated to EN61000-4-4 severity 4, which helps in a cabinet full of variable-speed drives. It also monitors its own signal quality and flags issues like undervoltage, disc contamination, or the LED nearing end of life, rather than failing silently.
From our experience, before we quote this, we would normally check the shaft type needed, solid or hollow, the housing diameter that fits the motor, and the exact sin/cos signal level the drive expects, since not every drive reads the same sinewave output the same way. Hope this helps.
