User`s manual

B-12 Motion Mate™ DSM314 for Series 90™-30 PLCs User's Manual – January 2001 GFK-1742A
B
PLC Data Start Pointer Offset (Word 10):
This word contains the offset within the memory
type selected in the PLC Data Memory Type word (Word 9).
Note: The PLC Data Start Pointer
Offset is a zero-based number.
In practical terms, this means that you should subtract one from
the address number that you wish to specify. For example, to select %R0001 as the PLC Data
Start location, enter zero (1 – 1 = 0). Or, to select %R0100, enter 99 (100 – 1 = 99). Note that
the memory type, %R in this example, is specified in the previous word. The starting address
designated by this word will be the first of 1024 contiguous words of PLC memory used in the
COMM REQ.
User Data Table COMM REQ Example
In this example, the following specifications are given:
•
The DSM314 module is mounted in Rack 0, Slot 7 of the PLC.
•
The Command Block’s starting address is %R0196.
•
The Status Word is located at %R0195.
•
The COMM REQ’s FT (fault) output drives a Set Coil.
•
Segment 1 of the DSM314 User Data Table is to be Written to. This is specified by the
Command Code D001 in Word 7 of the Command Block.
•
The data in a 1024 word (2048 byte) portion of PLC register memory, %R0301 through
%R1324, is copied and written into Segment 1 (2048 bytes) of the User Data Table. (Note
that each %R word is two bytes in length.) This transfer of data is illustrated in the next
figure:
PLC CPU
R
egister Memory
DSM314 User Data
Table (UDT)
Segment 1
(2048 Bytes)
Segment 2
(2048 Bytes)
Segment 3
(2048 Bytes)
Segment 4
(2048 Bytes)
%R0000
%R0301
%R1324
B
yte 0000
B
yte 2048
B
yte 4096
B
yte 6144
B
yte 8192
1
024 Words
(
2048 Bytes)
Figure B-4. Data Transfer for Command Code D001 (Write to Segment 1)
D
ATA