KOLLMORGEN 63025-01C LS5F SERVOSTAR signal isolated by optocoupler

Description

KOLLMORGEN 63025-01C LS5F SERVOSTAR signal isolated by optocoupler

KOLLMORGEN 63025-01C LS5F SERVOSTAR signal isolated by optocoupler

For motor positioning and commutation, the SERVOSTAR SC can utilize a resolver, digital encoder (with or without hall-effect sensor signals), or sine encoder feedback. Danaher Motion Kollmorgen offers a variety of motors with options for these various feedback devices. The feedback requirements are discussed below.

The SERVOSTAR SC can use encoder feedback to monitor the motor shaft position. The encoder is an incremental device that indicates changes in position. The encoder resolution of the SERVOSTAR SC and the encoder equivalent output is fixed because it is a hardware characteristic of the encoder device. The encoder interface includes three groups of wires:

1. A/B (and complements) lines make up the encoder quadrature signals. The signals are received differentially through line receivers before being passed through a wire-break detection circuit.

2. The narrow Index pulse normally appears once per revolution and indicates a known physical position of the shaft. This pulse is received differentially through a line receiver before being passed through a wire-break detection circuit. This signal is hardware capturable.

3. Hall-effect sensor signals provide information representing the approximate absolute location of the motor shaft. From this information, the motor can sinusoidally commutate forward until the index signal is detected – at which time true position is known. These signals are isolated by an optocoupler and can be differential or open-collector type signals.

The recommended cable length when using the SERVOSTAR SC to source the encoder is no longer than 50 feet (15 meters). Long encoder cables tend to have high DC resistance that may create significant loading effects in the supply lines to the encoder. An option that would allow the use of longer lengths, implements a separate supply located at the motor to source the encoder. Quadrature signals returned to the SERVOSTAR SC are differentially connected, which normally do not constitute a problem with longer cable lengths.

The SERVOSTAR SC uses either single- (two poles) or multi-speed (multiple poles) resolver feedback to monitor the motor shaft position. The resolver functions similar to a transformer whose output is unique for any given shaft position (an absolute position feedback). The transformer is driven with a sinewave reference signal. Two AC signals are returned from the resolver into the Sine and Cosine inputs. All three of these sinewave signals are low-level and susceptible to noise.