Configuring Hardware and Communication Connections STEP 7.pdf

3.10.4 The Slot Model of DPV1 Slaves with I-Slaves
Configuring the Distributed I/O (DP)
Subject of article below is the visualization of the assignment of addresses (I/O
addresses and diagnostic addresses) to the slots within the DPV1 model. We shall
pay close attention to the addresses that do not carry user data and especially to
the configuration of those addresses.
The Slot Model for DPV1
With DPV1 (IEC 61158) a slave is built of slots in the same way as DP
(EN 50 170). The slot numbers are 0, 1, ...n. Slot 0 - a new slot - is of high
significance because it is representative of the complete DP Slave.
Representative means, for example, that interrupts triggered via slot 0 are
assigned quasi to the global DP slave rather than to a certain slot within the DP
Slave. Diagnostics output from this slot are globally assigned to the DP Slave
rather than to any individual slot or module.
Excursion: Addresses for DP Interface
Seen from the CPU, a separate logical address is available for every one of your
interfaces.
You can locate this address in the "Addresses" tab of the Master interface and of
the Slave interface (double-click on the "DP" row in the configuration table ).
These addresses have nothing in common with the slot model of DP Slaves.
Rather, they are used by the CPU internally for the identification of, for example,
the failure of an interface. This address is of little significance to the user program.
Configuring Hardware and Communication Connections with STEP 7
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