E.g. For A 4096 Line Encoder The Maximum Rpm Would Be; 4096 = 7324 Rpm - Emerson SI-Universal User Manual

3.4.4 Incremental plus comms (absolute encoders) SC Hiperface, SC EnDat
and SC SSI
Type Encoder
Incremental
Hiperface
plus
comms
EnDat
(absolute
SC SSI
encoders)
SC BiSS
The SC Hiperface and SC EnDat encoders can be considered as a mixture of an incremental
encoder (analog SinCos feedback signals) and an absolute encoder (serial link used for absolute
position). The only difference between the encoders being the serial link protocol.
The RS 485 serial link allows the drive at power up to interrogate the SinCos encoder in comms
channel order to determine the initial absolute position of the encoder shaft. When the interrogation
is complete and the initial absolute position is known the position is incremented from the absolute
value using the analog sine/cosine interface.
The comms channels can then be used for either error checking, Pr 1x.040 or data transfer,
Pr 1x.068 to Pr 1x.069. The incremental SinCos plus communications encoder can be used when
operating in either RFC-A or RFC-S modes.
NOTE
A flux alignment test is required during set up to determine the phase offset angle for operation in
servo mode. The results of the alignment test are stored in EEPROM and do not need to be done
after every power up.
NOTE
The position retrieved during the initalization is compared to the partial position calculated from the
measurements of the Sine and Cosine signals. If they do not agree within a certain tolerance a trip
is generated.
Type
Incremental plus
communications
* Max input frequency = LPR x max rpm / 60
NOTE
The maximum speed in rpm which an encoder connected to the SI-Universal Encoder can achieve
can be calculated from:
Max rpm = (60 x Max input frequency) / Encoder LPR

e.g. For a 4096 line encoder the maximum rpm would be:

3
(60 x 500 x 10

) / 4096 = 7324 rpm

NOTE
The absolute maximum input frequency for any SC, SinCos encoder used with the SI-Universal
Encoder Module is 500 kHz.
14
SC Absolute SinCos encoder using Stegmann RS485
comms protocol (HiperFace).
SC
Absolute SinCos encoder using EnDat comms protocol.
Absolute SinCos encoder using SSI comms protocol.
Absolute SinCos encoder using BiSS comms protocol
Encoder Max Input Frequency *
SC Hiperface
Table 3-2
SC EnDat
information based on
frequency and voltage
SC SSI
SC BiSS
Description
Limitations
Interpolated
level
on page 11
SI-Universal Encoder User Guide
Pr 1x.038
Max no. of Max Baud
Lines (LPR) Rate (bits/s)
9600 (fixed)
100,000
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