Accessing data on the ID 40/MDT 47/176
3 842 530 344/2014-05, MIT: ID 40,
Bosch Rexroth AG
6.9 MDT lifeguarding
MDT lifeguarding monitors the
presence of an MDT in the
CONNECTED
state
. If the
MDT leaves the HF field without signing off through DISCONNECT or RECONNECT,
the SLK automatically switches to the
ERROR
state.
This results in the following properties:
• With an SLK in the link state
CONNECTED
, it is guaranteed that an MDT is present
and read and write access within the memory capacity of the MDT is unrestricted.
• The “Open transfer” and “Close transfer” functions are no longer needed
(described in Chapter 6.6 of the ID 40 system manual version 3.0). MDT
lifeguarding ensures the consistency of the transmitted data packets.
• MDT lifeguarding also prevents an MDT from signing on again unexpectedly, since
the HF field is off while in the
ERROR
state.
Tips for the application:
• Only access the MDT when the link state is
CONNECTED
. If ERROR appears
between related data transfers, the MDT data set is inconsistent.
• No longer use commands to open and close the transfer.
• If MDT lifeguarding unexpectedly switches to the
ERROR
state, the sequence
programs need to be checked. This can be caused by a stop gate that opens too
early. Or the DISCONNECT or RECONNECT command was not sent to the SLK.
• Proximity switches to detect a workpiece pallet are no longer needed if no
additional redundancy is desired.
PROOF COPy 1 | 20.05.2014 | FOR INTERNAL USE ONLy
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