Slk Operative Flag; Look Ahead Function; Slk Device Information - Bosch Rexroth ID 40 Manual

The connection switches to the DISCONNECTED state (display shows "off"). To
communicate with another MDT, the link state with the command-oriented data
exchange has to be switched back to CONNECTING.
It is not possible to access an MDT through a command-based data exchange in
either variant of auto mode.
5.3.4

SLK operative flag

The SLK operative information indicates a system restart by the SLK setting the
SLK operative flag to one after boot up. This gives the application the opportunity
to check, for example, whether or not the SLK performed a restart after a voltage
interruption.
To do this, the application sets the SLK operative flag to zero during boot up. Should
the SLK unexpectedly restart after an interruption in supply voltage, the application
can place its own sequencers in their initial state after evaluating the data block and
place the SLK back in the desired link state.
5.3.5

Look ahead function

The look ahead function supports the reading of MDT data from a data block
addressed through one of the three MDT pointers.
When an MDT pointer is read, the SLK not only retrieves the corresponding pointer
value from the MDT, but also data bytes addressed by the pointer value. The number
of the data bytes can be adjusted with an entry in the Look Ahead Control SLK
register.
The value zero in the Look Ahead Control register deactivates the look ahead
function. In this case, only the pointer is read from the MDT.
The data from the user data area is only saved in the SLK and not returned through
the event- or command-oriented data exchange.
Make sure that the entire data block falls within the MDT's user data area, i.e., the
MDT address saved in the read pointer plus the current value of the Look Ahead
Control register have to produce an MDT address within the user area. If this
address area is exceeded, the prohibited data is flagged with an error in the SLK
memory. When reading this data, the system returns the error "MDT communication
interrupted".
A look ahead is naturally executed during prefetch. In fact, the MDT data saved in the
SLK can only be read when the MDT has left the HF field. This supports time-critical
applications in conjunction with the auto reconnect function.
5.3.6

SLK device information

The SLK device information refers to the four-digit SLK software version and the SLK
device name, for example: ID 40/SLK-PDP. This information is constant and cannot
be modified.
SLK memory structure
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