
80
SM-Universal Encoder Plus User Guide
www.controltechniques.com
Issue Number: 6
For any type of linear encoder one revolution is the motor pole pitch multiplied by the
number of poles set up in Pr
5.11
.
Ab, Fd, Fr, Ab.SErvo, Fd.SErvo and Fr.SErvo
The incremental signal frequency should not exceed 600kHz. SC.HiPEr, SC.EndAt,
SC.SErvo, SC and SC.SSI
The encoder port is designed to give 10 bits of interpolation resolution at 115kHz. The
resolution is reduced at frequencies higher than 115kHz and at peak to peak differential
voltages less than 1 volt. The total resolution in bits per revolution is the ELPR plus the
number of bits of interpolated information.
The table below shows the number of bits of interpolated information at different
frequencies and with different voltage levels at the drive encoder port.
If the position feedback device is a rotary SINCOS encoder with comms the position
supplied via comms gives a number of counts per revolution that is a power of two and
the resolution is defined by the single turns comms bit (Pr
x.11
).
When Pr
x.11
is adjusted an "Initialisation failed - 7" trip is produced, because the
encoder requires re-initialisation.
EndAt, SSI
Where encoder comms alone is used as position feedback, the equivalent lines per
revolution (Pr
x.10
) is not used in setting up the encoder interface. It is possible for the
drive to set up this parameter automatically from information obtained from an EndAt
encoder (see Pr
x.18
).
The equivalent lines per revolution in Pr
x.10
can be divided where required using
Pr
x.46
line per revolution divider.
Example 128.123 lines per revolution would be set as 128123 in Pr
x.10
and 100 in
Pr
x.46
giving 128123 / 1000 = 128.123
Where encoder comms is used for initial setting of absolute position (SC.HiPEr or
SC.EndAt), the comms resolution in bits must be set correctly, either by the user or the
Position feedback device
ELPR
Ab, Ab.SErvo
number of lines per revolution
Fd, Fr, Fd.SErvo, Fr.SErvo
number of lines per revolution / 2
SC.HiPEr, SC.EndAt, SC, SC.SErvo number of sine waves per revolution
The absolute maximum sine wave signal frequency is 166kHz (version
3.x.x
) 250kHz
(version
4.x.x
).
Volt/Freq
1,000
5,000
50,000
100,000
150,000
200,000
250,000
1.2
11
11
11
10
10
9
9
1.0
11
11
10
10
9
9
8
0.8
10
10
10
10
9
8
8
0.6
10
10
10
9
9
8
7
0.4
9
9
9
9
8
7
7
200kHz and 250kHz are not available with hardware versions less than
4.x.x
x.11
Single turns comms bits/ linear encoder comms bits
RW
Uni
US
Ú
0 to 32 bits
Ö
0
Update rate: Background read
NOTE
NOTE
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