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Beckhoff
4.8.2
SSI encoder emulation - position output (X5)
The SSI interface (synchronous serial absolute-encoder simulation) is part of the delivered
package. Select the encoder function SSI (screen page "Encoder"). In the servo amplifier, the posi-
tion of the motor shaft is calculated from the cyclically absolute signals from the resolver or encoder.
This information is used to create a position output in a format that is compatible with the standard
SSI-absolute-encoder format. 24 bits are transmitted.
SINGLE TURN selected: The upper 12 bits are fixed to ZERO, the lower 12 bits contain the posi-
tion information. For 2-pole resolvers, the position value refers to the position within one turn of the
motor, for 4-pole resolvers it is within half a turn, and for 6-pole resolvers it is within a third of a turn.
Exception: If an encoder with a commutation track is used as the feedback unit, then the upper 12
bits are set to 1 (data invalid!) until a homing run is performed.
MULTI TURN selected: The upper 12 bits contain the number of motor turns, the lower 12 bits con-
tain the position information.
The signal sequence can be output in Gray code (standard) or in binary code (parameter
SSI-CODE). The servo amplifier can be adjusted to the clock frequency of your SSI-evaluation with
the SSI-TAKT parameter (cycle time 200 kHz or 1.5MHz and inverted).
The drivers are supplied from internal supply voltage.
PGND must always be connected.
Connection and signal description for SSI interface :
The count direction is upwards when the motor shaft is rotating clockwise (looking at the shaft end).
- A.4.031.1/12
AX2040/2070 Installation Manual
AX2040/2070
02/06
Interfaces
57
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