User guide

Software
60
890 USE 108 00 August 2001
XMWT AND
XMRD Function
Blocks (E984-
251/255 Only)
The Extended Memory function blocks XMWT and XMRD function as described in
the Modicon Ladder Logic Block Library User Guide (840 USE 101 00) with two
exceptions, as noted below. The functions are available from the panel DX selection
when E984-251/255 is configured
The bottom input is ignored because the E984-251/255 can not detect memory
errors as it reads or writes to the extended memory.
The status word bits 14 and 15 are not used because the memory does not have
parity and the extended memory is not separated from the remainder of the
Controller memory.
XMWT Block: The top node refers to the address of the first reference to get for
transfer to the 6X area. The middle node and Reference Data shows the 6X
register control block associated with Extended Memory transfers.
The following figure shows the XMWT block.
1 = Enable
1 = Does not
clear offset
1 = Active
1 = Complete
400100
400400
XMWT
#00001
400100 Source_add
400401 Status
400402 File_Number
400403 Start 6X
400404 Count
400405 Nmbr_done
400406 Max_reg
0 Dec
1 Dec
9999 Dec (Max 9999)
9999 Dec (Max 9999)
0 Dec (Keeps running total of
transfers
9999 Dec (Max 9999)
Reference Data:
1 = Error