8BCOMMUNICATION WITH OTHER SYSTEMS
9.4 Writing data records to the module
If data records are to be written to SIWAREX U alongside the default value for the
remote display, which is updated cyclically, this can be done via the "
Number m for
writing DR(m)" and the specification of the value in the area "Variable of DR(m) for writing"
.
A write request is only accepted by SIWAREX U when the instruction bit is different
from the instruction acknowledgement bit. If an instruction was accepted, then
further instructions will only be accepted once SIWAREX U brings it about that the
instruction bits are the same, i.e. the data transfer has been completed. The
instruction bit is only required for the writing of data records.
One should proceed as follows:
• Query instruction acknowledgement bit in the Status input byte 1.7 (9.7) to see
whether it is identical with the instruction bit output byte 3.7 (11.7) in Task
Controlling.
• Transfer the desired data record number "m" to the output byte 1 (9).
• Transfer the desired value of the data record "m" to the output word 4 (12) and
invert the instruction bit in Task Controlling.
• Query the instruction acknowledgement bit in Status for as long as it takes to
verify whether the module has synchronized it from the instruction bit.
• If the instruction bit and instruction acknowledgement bit are identical, this
means that the task has been completed.
• Query data or operator errors. In the input byte 1 (9), (status byte), bit 1 is to be
queried.
• If a data or operator error has occurred, then data record 76 (synchronous
errors) can be read for detailed error information.
SIWAREX U
9-61
Summary of Contents for Siwarex U
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