Siemens SINUMERIK 828D Function Manual page 870

P3: Basic PLC Program for SINUMERIK 840D sl
13.7 Interface structure
• Bit fields for events related to the VDI interface are combined in a single data block (DB2) with bit fields for
user messages.
• Bit fields are evaluated at several levels by FC10.
- Evaluation 1; Acquisition of group signals
A group signal is generated for each group of signals if at least one bit signal is set to "1". This signal is
generally linked to the disable signal of the VDI interface (on modules with diagnostic functions). The
group signals are acquired completely in cycles.
- Evaluation 2; Acquisition of interrupt messages
A fixed specification exists to define which signals in a group generate an interrupt message when they
change from "0" to "1".
- Evaluation 3; Acquisition of operating signals
A fixed specification exists to define which signals in a group generate an operational message.
• The scope of the user bit fields (user area) is set by default to 10 areas with 8 bytes each, but the number of
areas can also be adjusted to suit the requirements of the machine manufacturer via basic program
parameters in FB 1.
Acknowledgment concept
The following acknowledgment procedures are implemented for error and operational messages:
Operating messages are intended for the display of normal operating states as information for the user.
Acknowledgment signals are, therefore, not required for this type of message. An entry is made in the diagnostic
status list for incoming and outgoing messages. The HMI maintains an up­to­date log of existing operating
messages using the identifiers "operating message arrived" and "operating message gone".
Interrupt messages are used to display error states on the machine, which will usually lead to the machine being
stopped. Where several errors occur in rapid succession, it is important to be able to distinguish their order of
occurrence for troubleshooting purposes. This is indicated, on the one hand, by the order in which they are
entered in the diagnostic buffer and on the other, by the time stamp, which is assigned to every entry.
If the cause of the error disappears, the associated interrupt message is only deleted if the user has
acknowledged it (e.g. by pressing a key on the MCP). In response to this signal, the "Message acquisition" FC
examines which of the reported errors have disappeared and enters these in the diagnostic buffer with the entry
"Interrupt gone". This enables the HMI to also maintain an up­to­date log of pending interrupt messages. The
time of day indicating the time at which the error occurred is maintained for messages, which are still pending (in
contrast to a received interrogation).
STEP 7
A tool can be started in the SIMATIC Manager via menu item "Target system" > "CPU messages". Alarms and
messages can be displayed by number using this tool. To do this, acivate the "Alarm" tab and enter a check mark
under "A" in the upper half of the screen.
870
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Basic Functions