V1503 - "SAS" - Page 9/16
ELECTRICAL CHARACTERISTICS
Number of bits 26 (25 data + 1 parity)
Counting resolution 0.1 µm
Data type Gray
Parity Odd
Time out 450 µs
Configuration of the SSI protocol
Values for SSI protocol in Fagor SAS linear encoders
1 V
incremental si
nals
Signals A, B, /A & /B
V
A
pp
1 V +20 %, -40 %
V
B
pp
1V +20%, -40%
DC offset 2.5 V 0.5 V
Signal period 20 m
Phase Shift A & B 90 º 10 %
V
A
/
V
B
0.8 V to 1.25 V
Freq@120m/min 100 kHz
Power supply V 5 V 10 %,
Power supply Imax 250 mA (no load) (sense possible)
Max cable length
100 meters. For lengths over 9 meters, a 1 m or 3
m cable and an extension cable must be used
whose characteristics are:
(4x2x0.14+4x0.5+(4x0.14)) mm
2
Absolute signals
Transmission SSI synchronous serial data transfer via RS-485
Levels EIA RS-485
Clock frequency 100kHz - 500kHz
Max bits (n) 32 (configurable)
T1 s to 10 s
t
1
> 1 s
t
2
20 s to 35 s
SSI Gray or binary (configurable)
Parity Fully configurable
Specification
Specification
T
MSB LSB
1 2 3 n-1
n
t
1
t
2
Clock sequence
V
A
V
B
90º
20 m
1V
1V
