ABB REL 356, Instruction Booklet

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LINE SECTIONALIZING USING A PLC AND ABB PROTECTIVE RELAY
Page 18 of 53
Figure 30. Segment 3 Network 2 – Cyclic Poll Pointer Setup Logic
SEGMENT 3 NETWORK 3:
This network seems to be rather complex, but it really is not. The XMIT block needs two types of
parameterization 1) parameterization of the block for delay parameters, timeout parameters and definition
of pointers for the MODBUS data gatheringwhich is in registers 40308 through 40315. 2) the
parameterization of the Modbus commands which are pointed to by registers 40309 and 40310 (which is
the address of the 5 registers for command parameterizations) and the length of the parameter block
(which is 5 and its structure depends upon the instruction, please reference the MODICON XMIT BLOCK
documentation for a more complete discussion of the data).
The XMIT instructions are stored in FILE 2 and FILE 1 of 6X memory beginning at addresses 600500 and
610500 respectively. File 1 parameterizes the XMIT block parameters and FILE 2 parameterizes the
particular MODBUS request. The mathematics of this block calculates the data in the following way:
FILE 1 POINTER (Reg 40334) = Pointer (Reg 40331 * 10) + 500 offset.
FILE 2 POINTER (REG 30337) = Pointer (Reg 40331 * 30) + 500 offset.
The File 1 pointer is passed to the XMRD block which transfers 7 registers to the XMIT parameterization
space 40308 to 40315. The File 2 Pointer is passed to the XMRD block which sends 30 registers from
6X memory to 40355 to 40384. Figure 31 illustrates the parameterization which must occur in order to
allow the XMIT block to gather the data successfully. As is illustrated in Figure 31 the PLC stores the
data in PLC register 41700 through 41849. The PLC program has been optimized for data storage and
grouped register usage. This program may be expanded to perform other functions.