# Velocity units

Velocity and acceleration conversions can be calculated in two phases:

1. Computing the feedback resolution.
2. Applying the conversion factors of the desired units.

## Computing feedback resolution

### Velocity

The velocity resolution depends directly on the feedback used and is based on EMCL units (c/s). EMCL supports as velocity feedbacks:

• Tachometer
• Velocity estimator from Position Sensor

#### Tachometer

The resolution of the tachometer is computed as follow: (both Velocity Encoder Resolution and Motor Revolutions Per Second from register 0x6090)

#### Velocity estimator from Position Sensor

The resolution based on the position sensor can be found in the next link. In this case, the velocity resolution is the same than the position resolution.

### Acceleration / deceleration

The resolution of the acceleration / deceleration parameters are based on the position sensor. Therefore, the acceleration / deceleration resolution is always the same than the position resolution. Further information can be found in the next link.

## Applying the conversion factors of the desired units

A direct conversion factor can be applied to obtain the desired units after the computation of the resolution. The next sections shows the conversions of the most typical units.

### Velocity

#### mm/s

For linear Voice coils the pole pitch variable is equal to the stroke (SubIndex 0x05). Otherwise, the pole pitch value is the pole pitch (SubIndex 0x03)

#### um/s

For linear Voice coils the pole pitch variable is equal to the stroke (SubIndex 0x05). Otherwise, the pole pitch value is the pole pitch (SubIndex 0x03)

### Acceleration / deceleration

#### mm/s2

For linear Voice coils the pole pitch variable is equal to the stroke (SubIndex 0x05). Otherwise, the pole pitch value is the pole pitch (SubIndex 0x03)

#### um/s2

For linear Voice coils the pole pitch variable is equal to the stroke (SubIndex 0x05). Otherwise, the pole pitch value is the pole pitch (SubIndex 0x03)

## Related registers

0x6090 - Velocity encoder resolution

0x2701 - Motor parameters

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