Control Techniques SM-Resolver - Page 25

SM-Resolver User Guide 25
Issue Number: 4 www.controltechniques.com
Pr x.04 and Pr x.05 give the position with a resolution of 1/2
16
ths of a revolution as a 32
bit number as shown below.
Provided the set-up parameters are correct, the position is always converted to units of
1/2
16
ths of a revolution, but some parts of the value may not be relevant depending on
the resolution of the feedback device. For example if 10 bit resolution is selected the
resolver produces 4,096 counts per revolution, and so the position is represented by the
bits in the shaded area only.
When the feedback device rotates by more than one revolution, the revolutions in Pr
x.04 increment or decrement in the form of a sixteen bit roll-over counter.
x.04 Revolution counter
RO Uni FI NC PT
Ú
0 to 65,535 revolutions
Ö
Update rate: 4ms x number of dumb modules
x.05 Position
RO Uni FI NC PT
Ú
0 to 65,535 (1/2
16
ths
revolutions)
Ö
Update rate: 4ms x number of dumb modules
31 16 15 0
Revolutions Position
31 16 15 4 3 0
Revolutions
Position
The internal update time for the position Pr x.03 and Pr x.05 when used as feedback runs
at level 1, this being switching frequency dependant as follows.
NOTE
Update time Switching frequency Level
167µs3kHz 1
125µs 4kHz, 8kHz, 16kHz 1
83µs 6kHz, 12kHz 1
The internal update time for the speed Pr x.03 when used as feedback runs at level 2 as
follows.
NOTE
Update time Switching frequency Level
250µs
3kHz, 4kHz, 6kHz,
8kHz, 12kHz, 16kHz
2