Siemens S120 Manual page 375

Table 8- 19 Encoders that can be connected
HTL bipolar 24 V
HTL unipolar 24 V
1)
TTL bipolar 24 V
TTL bipolar 5 V
SSI 24 V/5 V
TTL unipolar
Because the physical transmission media is more robust, the bipolar connection should always be used. The unipolar
1)
connection should only be used if the encoder type does not output push-pull signals.
A controller compares the encoder system supply voltage - sensed via the Remote Sense cables - with the reference
2)
supply voltage of the encoder system, and adjusts the supply voltage for the encoder system at the output of the sensor
module until the required supply voltage is obtained directly at the encoder system (only for 5 V encoder system power
supply).
Maximum encoder cable lengths
Table 8- 20
Encoder type
TTL
HTL unipolar
HTL bipolar
SSI
1)
2)
3)
AC Drive
Manual, (GH6), 04/2014, 6SL3097-4AL00-0BP4
Supplementary system components and encoder system integration
X520
(SUB-D) (terminal)
Yes
Yes
connection is recommended)
Yes
Yes
Yes
Maximum encoder cable length
1)
2)
For TTL encoders at X520 → remote sense → 100 m
Because the physical transmission media is more robust, the bipolar connection should always be
used. The unipolar connection should only be used if the encoder type does not output push-pull
signals.
See the diagram "Maximum cable length depending on the SSI baud rate for SSI encoders"
X521 X531
(terminal)
Yes
Yes (however, a bipolar
Yes
Yes
Yes
no
Track
monitoring
Yes
no
1)
Yes
Yes
no
Maximum encoder cable length in m
100
100
300
100
3)
8.1 Sensor Modules
Remote Sense
2)
no
no
no
At X520
no
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