Ssi Data Transmission - Kübler Sendix SIL Série Instructions D'utilisation

4.1.2 Differential signal measurement
Measured differentially, the sine and cosine signals have an amplitude of 1 Vss, with a phase-shift
of 90°. Depending on the variant, the resolution of the incremental track is 1024 or 2048 sine/cosine
periods per revolution.
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4.2 SSI data transmission

The absolute position is transmitted via the SSI interface to the controller in the form of a digital data
word.
The serial, differential transmission consists of two clock lines and two data lines. The controller sends
clock pulses via the clock line and the encoder supplies the position data via the data line. A terminat-
ing resistor of 120 ohm must be connected to the data line at the controller input.
In the rest state, the clock and data lines are at high level. With the first falling clock-pulse edge, the
current encoder data is stored in the buffer, ready to be sent. With the following rising clock-pulse edg-
es data is transmitted bit by bit, starting with the MSB (Most Significant Bit). The transfer of a complete
data word requires n+1 rising clock-pulse edges (n = resolution in Bit), e.g. 14 clock signals for a com-
plete readout of a 13 bit encoder. After the last positive clock-pulse edge the data line will remain at a
low level for the duration of the monoflop time t3 until the encoder is again ready for a new data word.
The clock line must stay High for at least the same amount of time, and can then again initiate a new
read-out sequence of the encoder with a falling edge.
SIN
COS
t1 = T / 2
t2 < 1 / (4 x fmax)
t3 = Monoflopzeit (s. unten)
n = Auflösung in Bit
1/ fmax =< T =< 1 / fmin
fmin = min. SSI-Taktrate
(s. Datenblatt)
fmax = max. SSI-Taktrate
(s. Datenblatt)
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( R6 070 9.0 009 )