SICK DL100 Pro

8024484/2019-06-06 • © SICK AG • Subject to change without notice 109
“SSI” interface
11 “SSI” interface
11.1 Basics
The SSI (synchronous serial interface) makes it possible to receive abso-
lute information about the position using serial data transfer. Clock and
data are transferred over the interface.
The data is transferred upon request from the control system. The cycle
time and transmission rate can be adjusted in wide limits. For this purpose,
the connected control unit applies a clock sequence to the receiving input
of the distance measuring device. At each positive pulse edge, a data bit
is pushed onto the distance measuring device´s transmission line. This
starts with the highest-value bit. There is a pause of at least 30 µs be-
tween two pulse sequences. The bit pulse is between 70 kHz and 500 kHz
andisdependentonthelengthofcable.ThemonooptimeoftheDL100
Pro is 21 µs.
Transfer rate
Cable length [m] Transmission rate [kbaud]
< 25 < 500
< 50 < 400
< 100 < 300
< 200 < 200
< 400 < 100
Table 61: Transmission rate in relation to the length of cable
Pulse diagram
Gn Gn-1 G1 G0
tm
T
tv
T
p
m
m+1m
m–1
 
Cycle
Data serial
Monoflop P/5
Data parallel
Fig. 27: Pulse diagram of data transmission
Gn Highest-quality bit in gray code
G0 Lowest-quality bit in gray code
m Saved parallel information
tm Monoop time 15 … 25 µs
tv Delay time: First clock max. 540 ns, all other clocks max. 360 ns
T Period duration of the clock
Tp Clock break