User`s manual

DSM314 COMM REQ
GFK-1742A Appendix B DSM314 Communications Request Instructions B-11
B
Status Word Pointer Offset (Word 4):
This word contains the offset within the memory type
selected.
Note: The Status Word 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, enter a zero (1 – 1 = 0). Or, if you want to specify %R0100, enter a
99 (100 – 1 = 99). Note that the memory type, %R in this example, is specified by the previous
word (see the “Status Word Pointer Memory Type” explanation above).
Idle Timeout Value (Word 5):
Since the DSM always uses the NOWAIT mode (WAIT/NOWAIT
flag always set to zero), this Idle Timeout Value parameter is not used for the DSM. Set it to zero.
Maximum Communication Time (Word 6):
Since the DSM always uses the NOWAIT mode
(WAIT/NOWAIT flag always set to zero), this Maximum Communication Time parameter is not
used for the DSM. Set it to zero.
Command Code (Word 7):
Use one of the eight Command Codes from the table below. The
Command Codes are given as hexadecimal numbers.
Table B-5. UDT COMM REQ Command Codes
User Data Table (UDT) COMM REQ Commands
Command Code Command Description
D001h Write to UDT Segment 1
D101h Write to UDT Segment 2
D201h Write to UDT Segment 3
D301h Write to UDT Segment 4
D804h Read from UDT Segment 1
D904h Read from UDT Segment 2
DA04h Read from UDT Segment 3
DB04h Read from UDT Segment 4
UDT Segment Data Size (Word 8):
Specifies the memory size, in bytes, of the UTP Segment to
be accessed. This value should always be 2048 bytes (800h for hexadecimal).
PLC Data Memory Type (Word 9):
This word specifies the memory type that will be used for
PLC Data. Each memory type has a unique code number, shown in the Memory Type Codes table
below. So, for example, to specify %R memory, you would put either the decimal code number 8
or the hexadecimal code number 08h in this word.
Note
The UDT COMM REQ does not support discrete memory (%I or %Q) for
the PLC Data Memory Type.
Table B-6. PLC Data Memory Type Codes for UDT COMM REQ
UDT COMM REQ PLC Data Memory Type Codes
Code Number to Enter
Memory Type
Abbreviation
Memory Type
Decimal Hexadecimal
%R Register memory 8 08h
%AI Analog input table 10 0Ah
%AQ Analog output table 12 0Ch