Velocity, speed calculation

In addition to the counter value, the velocity and speed an also be measured. The measured values are determined through parameterization of the frequency values. The following limit values apply:

Measured value output

Measured value limit

Comment

lower

top

Frequency value

0.095 Hz

5 MHz

with 4-fold evaluation
Signal type: RS422 (diff. input)

0.095 Hz

1 MHz

with 4-fold evaluation
Signal type: TTL (single ended)

0.095 Hz

100 kHz

with 4-fold evaluation
Signal type: open collector

The frequency measurement is carried out as described in chapter "Frequency measurement (Frequency value)". In addition, the frequency value can be converted using the two indices 0x80n0:1D "Frequency numerator" and 0x80n0:1E "Frequency denominator".

Index (hex)

Name

Meaning

Default

80n0:1D

Frequency numerator

Frequency numerator
Factor for normalizing the frequency, e.g. the time unit

0x0000001 (1dec)

80n0:1E

Frequency denominator

Frequency denominator,
Factor for normalizing the frequency, e.g. speed calculation

0x0000001 (1dec)

Thus, the frequency can be normalized for application-specific speed measurement. The measured value continues to be output in the process data via "Frequency value" (index 0x60n0:13).

The calculated measured value has the following relationship to the frequency:
Velocity, speed calculation 1:

Example for velocity calculation in m/s

The velocity value is determined as follows:
Velocity, speed calculation 2:

Index (hex)

Name

Example: velocity in m/s

Comment

80n0:1D

Frequency numerator

0x00000C8 (200 dec)

Travel path, conversion to m via "Frequency denominator"

80n0:1E

Frequency denominator

0x003E8000 (4096000 dec)

Specification of the number of periods over the travel path and conversion of the travel path to m

Example Calculation of speed frot in revolutions/s

Conversion to minutes depending on "Frequency scaling"

Index (hex)

Entry

Index (hex)

Entry

0x80n0:13 Frequency scaling

100dec: 0.01 Hz

0x80n0:1D Frequency numerator

0x00001770 (6000dec)

1dec: 1 Hz

0x0000003C (60dec)

Velocity, speed calculation 3:

Index (hex)

Example: Speed
frot in rpm

Comment

80n0:1D Frequency numerator

0x0001770 (6000 dec)

Output of the value in 0.01 rpm

80n0:1E Frequency denominator

0x0001000 (4096 dec)

Conversion factor in periods / m