Generic item format
Regardless of the client application used with RSLinx Classic, the address of the DDE item specified must be of the following form:
[address]<,L##><,C##><R##>{,N}{,D}{,E}{,DH}{,EH}(,T)(,B)(,W)(,X)(,M) (,SA##)(,SC##)(,SP##)(,SS##)(,SA##)
where:
[ ] | indicates a required field (address) that is suitable for the PLC type specified within the topic. |
< > | indicates an optional block read or block formatting command. |
L## | indicates the total length (block size), or number of items to be read. |
C## | indicates the number of columns in which to format the data. This is for display purposes in the client application. |
R## | indicates the number or rows in which to format the data. This is for display purposes in the client application. |
## | indicates a numeric value that must be placed after the optional specifier. |
(Specifying C## without a corresponding L## specifier has no effect. However, specifying an L## without a C## results in a display as if L##,C1.) | |
{ } | indicates an optional data type specifier that is only used with a PLC-2. If none of these specifiers is used then the default type is N, 16-bit signed integer. |
M: | used for specifying a Motorola byte ordering, which causes the conversion routines to swap bytes before interpreting the data. This was mainly intended to fix a problem when reading strings with unsolicited messages. |
N: | 16-bit signed integer |
D: | 12-bit, 3-digit BCD number |
E: | 16-bit, 4-digit BCD number |
DH: | 12-bit, 3-digit BCD number, displays the hexadecimal value |
EH: | 16-bit, 4-digit BCD number, displays the hexadecimal value |
(T) | indicates a special specifier used only with unsolicited messages when the source of the data table is a PLC-5 timer accumulated value and the destination address is something other than another timer accumulated value. In most situations this specifier is not needed. |
(B) | indicates a special specifier used only with the Allen-Bradley PLC data types that are 16-bits. This specifier causes the data to be displayed as a string of 1's and 0's instead of an unsigned integer. |
(W) | indicates a special specifier used only with the Allen-Bradley PLC data types. This specifier is used when specifying an array of bits. It causes data to be read from consecutive elements. For example in a structured data type (timers, counters, and so on), T4:0.DN,L10,C1,W reads T4:0.DN, T4:1.DN, T4:2.DN, etc. For a non-structured type (binary, integer, etc.), B3/0,L10,C1,W reads B3:0/1, B3:1/1, B3:2/1, etc. |
(X) | indicates a special specifier used only with the Allen-Bradley PLC data types. This specifier is used when specifying an array of bits. It causes data to be read from consecutive bits. For example in a structured data type (timers, counters, etc.), T4:0.DN,L3,C1,X reads T4:0.DN, T4:0.TT, T4:0.EN. For a non-structured type (binary, integer, etc.), B3/0,L10,C1,X reads B3:0/1, B3:0/2, B3:0/3, etc. |
(SA##) | sends all updates to the client RSLinx Classic receives even if they have not changed. |
(SC##) | indicates a special specifier used only with the Allen-Bradley Integer (N) or ASCII (A) PLC data types for C style strings. |
(SP##) | indicates a special specifier used only with the Allen-Bradley Integer (N) or ASCII (A) PLC data types for Pascal style strings. |
(SS##) | indicates a special specifier used only with the Allen-Bradley Integer (N) or ASCII (A) PLC data types for space-padded strings. |
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