GE VersaPoint IC220PBI002 User Manual page 152

8
Index 3: Control Byte
The parameter telegram provides a user-specific byte for the NIU, which can be
used to select the diagnostic format. In addition to transmission in the parameter
telegram (byte 11) it is also possible to specify the byte under index 3 and
therefore to change the parameters during operation.
Bit 0
Bit 1
Bit 3 to bit 2
Bit 4
Bit 5
Bit 6
Bit 7
As mentioned, the behavior in the event of a local bus error is set via the
parameter telegram. Please note that "Stop on error (local bus)" indicates that the
local bus switches to the STOP state after 10 consecutive faulty data cycles. In the
case of "No stop on error (local bus)", an attempt is made continuously to keep the
local bus operating and to automatically restart the local bus following error
removal. The set behavior only takes effect in the event of errors in the local bus.
Index 4: Acknowledgment of Local Bus Event
By default, I/O errors are acknowledged automatically and the local bus remains in
the Run state whenever possible.
Depending on the application, automatic acknowledgment may not be permitted
and special measures may be required. In this case it is possible to respond to
bus events manually via index 4. This applies for an error on a module (I/O error
that has to be acknowledged), and also after a serious error prevents further data
communication.
Bit 0
Bit 1
Bit 7 to bit 2
8-32 VersaPoint™ I/O System Profibus-DP NIU User's Manual – August 2005
0 No stop on error (locall bus)
1 Stop on error (local bus
0 Automatic error acknowledgement (eg: on I/O errors)
1 Manual acknowledgement requierd
00 Status PDU format
01 ID-specific diagnostics
0 DI 16 and DO16 format byte 0/byte 1
1 DI16 and DO16 format bte 1/byte 0
0 Data exchange with broadcast "Operate"
1 Data exchange without broadcast "Operate"
0 DI 32 and DO32 format slot 1/2/3/4 – byte 3/2/1/0
1 DI32 and DO32 format slot 1/2/3/4 – bute 0/1/2/3
Reserved
Acknowledgement of local bus stop
I/O error acknowledgement
Reserved
GFK-1911B