Detailed description
2.6 Interface structure
Power Line Basic PLC Program (P3)
2-38 Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
• 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 when 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
– Error messages
A fixed specification exists to define which signals in a group generate an error
message when they change from "0" to "1".
– Evaluation 3;Acquisition of
– Operational messages
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 defined as standard as 10 areas with 8
bytes each, but can also be adjusted to suit the requirements of the machine
manufacturer via basic program parameters in FB 1.
Acknowledgment procedures
The following acknowledgment procedures are implemented for error and operating
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 buffer for incoming and outgoing messages. The MMC
maintains an up to date log of existing operating messages using the identifiers "operating
message arrived" and "operating message departed".
Error messages are used to display error states on the machine which generally lead to a
machine stoppage. 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 error message is only deleted if the user has
acknowledged the message (e.g., by pressing a key on the machine control panel). 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 "error departed".
This enables the MMC to also maintain an up to date log of existing error messages. The
time of day indicating the time of error occurrence remains available for messages which are
still pending (in contrast to a received interrogation).
User program
The user PLC program merely needs to call the basic program block FC 10 with appropriate
parameter settings in the cyclic program section and set or reset the bit fields in DB2. All
further necessary measures are implemented by the basic program and MMC.
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