HEIDENHAIN PROFIBUS-DP (DPV0) - Manual (Page 39)

Encoder and Gateway functionality, DPV0
39
5.4.8 Velocity calculation
The velocity calculations are made with a maximum of
19 bits resolution. If the resolution is higher than 2 19 , the value
used for velocity calculations is automatically reduced to 2 19 . For a
multiturn encoder with 2 12 multiturn resolution, the maximum
singleturn value will be 2 19 and the velocity will be calculated on
the same resolution as presented in the diagnostic structure. For
a singleturn encoder the resolution can be up to 31 bit, but the
velocity calculations will be made on maximum 19 bits. This
means that in the diagnostic structure, the value 2 31 can be
presented, but the resolution used for velocity calculations is not
presented if the singleturn resolution is higher than 2 19 .
The parameter for velocity unit, octet 39 can be seen below:
Octet 39
Bits 7-0
Data 2 7 -2 0
Velocity control
Bit 7 6 5 4 3 2 1 0 Velocity unit
0 0 Steps/s
0 1 Steps/100 ms
1 0 Steps/10 ms
1 1 RPM (revolutions
per minute)
Table 15 Octet 39, Velocity Control
In case of steps/s unit, an average is made over 200 ms, and the value is multiplied by 5.