Menus 15 to 17
SM-Uni Enc Pl
Parameter
structure
Keypad and
display
Parameter
x.00
Parameter
description format
Advanced parameter
descriptions
Macros
Serial comms
protocol
Electronic
nameplate
Performance RFC mode
260 Unidrive SP Advanced User Guide
www.controltechniques.com Issue Number: 10
It should be noted that if the Pr x.19 the Feedback Filter is used where, the speed feedback is provided by either an EndAt or SSI encoder connected
directly to the module, it is necessary for the encoder to provide at least 6 bits of turns information. This is not a problem when the position is defined
by the absolute position from the encoder at initialisation and then accumulated delta positions (Pr x.16 = 0), however, if the absolute position is taken
directly from the encoder (Pr x.16 > 0) the encoder must provide at least 6 bits of turns information.
If the Feedback filter Pr x.19 is not used turns information from the encoder is not required.
When Ab, Fd, Fr, Ab.SErvo, Fd.SErvo, Fr.SErvo or SINCOS signals are used the equivalent number of encoder lines per revolution must be set-up
correctly in Pr x.10 to give the correct speed and position feedback. This is particularly important if the encoder is selected for speed feedback with Pr
3.26. The equivalent number of encoder lines per revolution (ELPR) is defined as follows.
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 500kHz.
SC.HiPEr, SC.EndAt, SC.SErvo, SC and SC.SSI
The absolute maximum sine wave signal frequency is 166kHz (version 3.x.x) 250kHz (version 4.x.x).
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.
200kHz and 250kHz are not available with hardware versions less than 4.x.x
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 drive (see Pr
x.18), in Pr x.11. The comms resolution may be higher than the resolution of the sine waves per revolution.
Ab, Fd, Fr, Ab.SErvo, Fd.SErvo, Fr.SErvo, SC, SC.SErvo
Pr x.11 has no effect.
SC.HiPEr, SC.EndAt, SC.SSI and x.16 = 1 or 2 (Rotary encoder)
Pr x.11 must be set to the number of comms bits used to represent one revolution of the encoder. The single turn comms resolution may be higher
than the resolution of the sine waves per revolution.
x.10 Equivalent lines per revolution
RW Uni US
Ú
0 to 50000
Ö
4096
Update rate: Background read
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
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
x.11 Single turns comms bits/ linear encoder comms bits
RW Uni US
Ú
0 to 32 bits
Ö
0
Update rate: Background read
To Next Page
Loading...
Need help?
General
