Standard Message Frames; Kernel Sequences - Siemens SINUMERIK 840 Planning Manual

6 Message Frames
6.1.2 Meaning of the characters used in the identification of "free message frames"
E = Single message frame (valid both in input and output direction)
N = Initial message frame of a message frame sequence (valid in input direction only)
M = Subsequent message frame of a message frame sequence (valid in input direction
only)
I = Terminating message frame of a message frame sequence (valid in input direction
only)
Block counter (character 8)
The block counter is operated by the procedure driver. All message frames received are
numbered consecutively. The block counter enables the user to join the blocks of a message
frame sequence in the correct sequence and thus detect the loss of any block. The counter is
implemented as a ring counter, i.e. a message frame sequence need not begin with 0.
6.2

Standard message frames

Standard message frames are those message frames which are processed by SINUMERIK
880 standard software in the COM or PLC area.
Standard message frames are:
• Event message frames
• Message frames for connection monitoring
• Mode switchover message frames
• Restart message frame
• Message frames for synchronization
• Message frames for file transfer
On receipt of a standard message frame a signal to the user interface is provided if required.
Some standard message frames have to be initiated via the standard interface (example:
Operator interrupt reporting ON/OFF).
6.3

Kernel sequences

Kernel sequences are defined message frame sessions between host computer and PLC
which are executed autonomously on the PLC side via the standard function blocks. Since the
kernel sequences are processed by the standard, these sessions are fixed and cannot be
changed by the PLC user program.
The message frames of the kernel sequences represent a subset of standard message
frames. Initiation of some kernel sequences is via the user interface "output".
If a message frame is acknowledged within a kernel sequence with an error, this results always
in the kernel sequence being aborted.
The tool data is entered through kernel sequences into the corresponding tool memories of the
SINUMERIK 8X0 on "random loading".
Use of the kernel sequences is only appropriate when the tool management software package
is integrated in the SINUMERIK 8X0 system.
6–6
© Siemens AG 1989 All Rights Reserved
06.91
6FC5 197-0AB20-0BP0
SINUMERIK 840/880 (PJ)