ABB REL 356, Instruction Booklet

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LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY
Page 21 of 53
Figure 35. Segment 3 Network 6 - XMIT Dwell Timer and Bad Transmission Counter
Logic
Segment 3 Network 7:
As with the Modbus Plus MSTR Logic, another FIFO has been constructed in which a manual control (or
automated control instruction initiated by the ladder logic may be performed). Note the FIFO may
contain up to 19 control instructions which may be queue’d for processing. Additionally, note the trigger
construct for pending FIFO commands to be sent to the XMIT block (coil 00309) interrupting the cyclical
poll. Using this philosophy ensures that control commands and operator initiated commands are
immediately scheduled for operation by the XMIT block.
Figure 36. Segment 3 Network 7 – FIFO Empty/Full Notification Logic
Segment 3 Network 8:
If the FIFO has data, this logic construct interrupts the polling of the XMIT instructions and immediately
parameterizes the block with the parameters pointed to within the FIFO queue. A dwell time of 100 mS
creates a pause for the XMIT instruction to terminate. The logic in SEGMENT 3 NETWORK 9 creates the