3
05.01
3.4 Direct position sensing
3-72
©
Siemens AG 2012 All Rights Reserved
SIMODRIVE 611 Configuration Manual (PJU) – 02/2012 Edition
The SSI encoder is used as direct position measuring system (NC) (SSI scale/
encoder is attached to the load). In addition to this direct position measuring
system, on the motor side, the speed is sensed using an incremental motor
encoder.
The exception is the measuring system sensing for SIMODRIVE 611D HLA,
where the linear scale can be used as ”motor measuring system”.
The used SSI encoders must comply with the following specification:
Gray or binary–coded encoders can be used under the assumption:
Error bit/alarm bit is the LSB; if, in addition, a parity bit is transferred, then
this is the next to last bit. If an alarm bit is not transferred, then the parity bit
is the LSB.
The net (useful) information – also as parity or error bit/alarm bit – are either
gray or binary–coded – but never mixed.
Message frame length (including alarm and/or parity):
–
SIMODRIVE HLA 13 and 25 bit,
–
SIMODRIVE 611D from 13, to 25 bit
Data format: SIMODRIVE HLA only right justified
For HLA: The encoder zero point of the linear encoder (absolute value 0)
must not be located in the traversing range.
Transfer frequency, f: 100 or 500 kHz.
Monoflop time:
–
at 100 kHz t
m
min 12
μ
s,
–
at 500 kHz t
m
min 2.4
μ
s,
–
or t
m
> 1.2
1/f
Operation is only possible without Safety Integrated!
Note
Only SSI encoders without incremental tracks may be used. The connection of
SSI encoders is not possible on the connection for the indirect measuring
system (X411, X412). The use as direct measuring system is possible only for
HLA axes.
3.4.2
Encoder power supply
Remote/sense operation is possible with the encoder power supply for the
motor measuring systems and the encoder power supplies for the measuring
systems for direct position sensing (voltage controlled directly on the encoder to
5%).
SSI encoder
3 Motor Selection, Position/Speed Sensing
05.08
