Siemens SINAMICS S120 Manual page 265

Table 9-20 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 supply
2)
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
Note
The maximum cable lengths according to the following table must not be exceeded even when
longer cable lengths can be calculated.
Table 9-21
Encoder type
TTL
HTL unipolar
HTL bipolar
SSI
For TTL encoders at X520 → Remote Sense → 100 m
1)
Because the physical transmission media is more robust, the bipolar connection should always be used.
2)
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"
3)
Control Units and additional system components
Equipment Manual, 06/2020, 6SL3097-5AH00-0BP2
X520 X521
(SUB-D) (terminal)
Yes
Yes
Yes
Yes
Yes
Maximum encoder cable length
1)
2)
9.6 Sensor Module Cabinet-Mounted SMC30
X531
(terminal) monitoring
Yes
Yes
1)
Yes
Yes
Yes
No
Maximum encoder cable length in m
Encoder system connection
Track Remote Sense
Yes No
No No
Yes No
Yes At X520
No No
100
100
300
100
3)
2)
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