Drive Encoder Type - Emerson unidrive sp User Manual

Menu 3 Parameter Keypad and
All modes structure display
SSI comms
The whole position must be obtained from an SSI encoder before it can be used by the drive, therefore the time for the single turn position and the
time for the whole message are the same.
Time to obtain the position= (Number of turns bits + Single turn resolution + 1) x T
= t
For example an encoder with 12 turns bits, 13 bit single turn resolution and a baud rate of 1M would give the following time:
Time to obtain the position data = 28μs (27.25μs rounded up)
The drive does not include the recovery time of the encoder in these calculations, therefore the user must ensure that there is sufficient time after the
data transfer before the next transfer begins. If the encoder does not recover in time its output will be low just before the new transfer beings and will
cause an Enc5 trip.

Drive encoder type

3.38
Drive modes Open-loop, Closed-loop vector, Servo
Bit SP
Coding
Range Open-loop, Closed-loop vector, Servo
Open-loop, Closed-loop vector
Default
Servo
Update rate Background read (Only has any effect when the drive is disabled)
The following encoders can be connected to the drive encoder port.
0, Ab: Quadrature incremental encoder, with or without marker pulse
1, Fd: Incremental encoder with frequency and direction outputs, with or without marker pulse
2, Fr: Incremental encoder with forward and reverse outputs, with or without marker pulse
This type of encoder can be used for motor control in closed-loop vector mode or servo mode. In servo mode a phasing test must be performed after
every drive power-up or encoder trip.
3, Ab.Servo: Quadrature incremental encoder with commutation outputs, with or without marker pulse
4, Fd.Servo: Incremental encoder with frequency, direction and commutation outputs, with or without marker pulse
5, Fr.Servo: Incremental encoder with forward, reverse and commutation outputs, with or without marker pulse
This type of encoder is normally only used in servo mode. If it is used in closed-loop vector mode the UVW signals are ignored. The UVW
commutation signals are used to define the motor position during the first 120° electrical rotation after the drive is powered-up or the encoder is
initialised. If the Drive encoder lines per rev (Pr 3.34) is set to zero the incremental signals are ignored and the drive can run with commutation
signals alone. A phase locked loop is used to smooth the feedback, but particularly at low speeds the motor movement includes a significant
ripple. Low speed loop gains should be used and the drive encoder filter (Pr 3.42) should be set to 16ms.
6, SC: SinCos: Encoder with no serial communications
This type of encoder can be used for motor control in closed-loop vector mode or servo mode. In servo mode a phasing test must be performed
after every drive power-up or encoder trip.
7, SC.Hiper: Absolute SinCos encoder using Stegmann 485 comms protocol (HiperFace).
This type of encoder gives absolute position and can be used for motor control in closed-loop vector or servo modes. The drive can check the
position from the sine and cosine waveforms against the internal encoder position using serial communications and if an error occurs the drive
initiates a trip. An applications or fieldbus Solutions Module can communicate with the encoder via parameters that are not visible from the
keypad or drive 485 comms.
8, EnDAt: Absolute EnDat only encoder
This type of encoder gives absolute position and can be used for motor control in closed-loop vector or servo modes. Additional communications
with the encoder from an applications or fieldbus module is not possible
9, SC.Endat: Absolute SinCos encoder using EnDat comms protocol
This type of encoder gives absolute position and can be used for motor control in closed-loop vector or servo modes. The drive can check the
position from the sine and cosine waveforms against the internal encoder position using serial communications and if an error occurs the drive
initiates a trip. An applications or fieldbus Solutions Module can communicate with the encoder via parameters that are not visible from the
keypad or drive 485 comms.
10, SSI: Absolute SSI only encoder
This type of encoder gives absolute position and can be used for motor control in closed-loop vector or servo modes. Additional communications
with the encoder from an applications or fieldbus module is not possible. SSI encoders use either gray code or binary format which can be
selected with Pr 3.41.
11, SC.SSI: SinCos encoder using SSI comms protocol
This type of encoder gives absolute position and can be used for motor control in closed-loop vector or servo modes. The drive can check the
position from the sine and cosine waveforms against the internal encoder position using serial communications and if an error occurs the drive
initiates a trip.
72
Parameter Parameter
x.00 description format
+ (Pr 3.33 + Pr 3.35 + 1) x T
D
FI DE Txt VM DP ND
1
0 to 11
0
3
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Advanced parameter
Macros
descriptions
RA NC NV PT US RW BU
1 1
Serial comms Electronic
Performance RFC mode
protocol nameplate
PS
1
Unidrive SP Advanced User Guide
Issue Number: 10