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5. Gateway Initialization and Diagnostics
5.3.2. Profibus-DP Master Control Word
The output word located at addresses 16#0200 (MSB) and 16#0201 (LSB) in the gateway’s output memory
constitutes the Profibus-DP master command word. Its structure is described below:
Bits Description
15
FB_HS_CONFIRM: Acknowledgement bit of a gateway diagnostic
The Profibus-DP master must compare the value of the FB_HS_CONFIRM bit to the value of the
ABC_HS_SEND bit (bit 15 in the gateway’s status word). If these two values are different, this means
that the gateway has transmitted a new diagnostic to the Profibus-DP master.
To tell the gateway that it has read a diagnostic, the Profibus-DP master must copy the value of the
ABC_HS_SEND bit to the FB_HS_CONFIRM bit. This allows the gateway to issue a new diagnostic.
Summary:
• If ( FB_HS_CONFIRM = ABC_HS_SEND ) Æ The gateway’s status word contains a diagnostic
which has already been acknowledged by the Profibus-DP master. So the gateway is free to use
this status word to place another diagnostic there.
• Else Æ A new diagnostic is available in the gateway’s status word. The Profibus-DP master can
read this diagnostic, but must also copy the value of ABC_HS_SEND to FB_HS_CONFIRM in
order to allow the gateway to generate new diagnostics.
0-14 Reserved.
5.4. Simplified Operation
The two 16-bit registers located at addresses 16#0000-16#0001 (inputs) and 16#0200-16#0201 (outputs) are no
longer used for “managing the downstream Modbus network”. These two registers are no longer reserved and
so these addresses can be used to exchange data with the Modbus slaves (“Data Location” attribute of “Data”
type frame fields).
The Profibus-DP master’s command word and the gateway’s status word, which we will be talking about in the
rest of this document, do not exist anymore. So the two warnings pages 55 and 60 should be ignored, and the
input and output ranges in the gateway’s memory therefore go respectively from 16#0002-16#00F3 to 16#0000-
16#00F3 and from 16#0202-16#02F3 to 16#0200-16#02F3.