Mdt Lifeguarding - Bosch Rexroth ID 40 Manual

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.
Accessing data on the ID 40/MDT
3 842 530 344/2014-05, MIT: ID 40, Bosch Rexroth AG
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