The absolute position is obtained after position feedback initialization via the comms interface and then after that point by tracking the incremental

change from the sine wave signals. Interpolation is used to increase the position resolution. The comms interface can be used to check the position

derived from the sine waves. It can also be used for bi-direction transfer of data between the drive and encoder (except SSI comms). These devices

can be used for motor control in RFC-A or RFC-S modes.

Absolute comms

The absolute position is obtained at all times via the encoder comms. The comms interface can also be used for bi-directional transfer of data

between the drive and the encoder (except SSI mode). These devices can be used for motor control in RFC-A or RFC-S modes.

SINCOS with absolute position from sine and cosine signals

This type of device, which is not recommended for new applications, is intended to provide absolute position feedback for motor control in RFC-S

mode. If one of these devices is used for RFC-A mode the additional sine wave signals and the Z1 marker signal do not affect the motor control

position feedback. The position information given in Drive Encoder Position (J53) and Drive Encoder Fine Position (J54) is initialized to the position

within one turn and Drive Encoder Revolutions (J52) is set to zero when the device is initialized based on the once per turn sine and cosine signals.

This gives a moderately accurate absolute position. When a marker event occurs it is used to give a more accurate absolute position. Care should be

taken to ensure that the position feedback device is connected correctly.

For example a Heidenhain ERN1387 device should be connected as follows: 1/2=A+/A-(Cosine), 3/4=B+/B-(Sine), 5/6=R+/R-(Marker), 7/8=C+/C-

(Single turn cosine), 9/10=(Single turn sine). It is assumed that the marker occurs at the positive zero crossing of the single turn cosine signal when

operating in the forwards direction (i.e. compatible with the ERN1387).

Communications

Hiperface

Hiperface is an asynchronous bi-direction communications protocol that is only used with incremental sine waves. Therefore it can be used to check

the position derived from the sine waves or for bi-direction transfer of data between the drive and encoder. A checksum is provided for error checking.

EnDat 2.1

EnDat 2.1 is a synchronous bi-direction communications protocol that is intended to be used with incremental sine waves. Therefore it can be used to

check the position derived from the sine waves or for bi-direction transfer of data between the drive and encoder. It can be used as an absolute

comms only type position feedback interface, but the resolution of the position feedback using this method may be limited. If it is used in this way it is

not possible to use the position feedback via comms at the same time as communicating with the encoder for data transfer. A CRC is provided for

error checking.

EnDat 2.2 and BiSS C Mode

EnDat 2.2. and BiSS are synchronous bi-direction communications protocols that are intended to be used alone. It is possible to obtain position

feedback at the same time as communicating with the encoder for data transfer. A CRC is provided for error checking.

SSI

SSI is a uni-directional communications protocol that is intended to be used alone. It is only possible to obtain the position information from the

encoder and it is not possible to transfer data between the drive and the encoder. No error checking is provided by the SSI protocol, and so encoders

based on this interface are not recommended for new applications.

C02

Mode

Minimum