Rockwell Automation 2706 DL40 HARDWARE USER MANUAL - Manual (Page 90)

Chapter 9
Using the Parallel Port
9 – 6
Table 9.G
Strobe line states specify type of data on the data lines
MS3 MS2 MS1 MS0 Data Type
0 0 0 0 null
0 0 0 1 D0–D15 contain the message number
0 0 1 0 D0–D15 contain the slave address
0 0 1 1 D0–D9 BDC sign bits for (Ctrl V) variables 1–10
1 0 0 0 D0–D15 contain variable 1
1 0 0 1 D0–D15 contain variable 2
1 0 1 0 D0–D15 contain variable 3
1 0 1 1 D0–D15 contain variable 4
1 1 0 0 D0–D15 contain variable 5
1 1 0 1 D0–D15 contain variable 6
1 1 1 0 D0–D15 contain variable 7
1 1 1 1 D0–D15 contain variable 8
0 1 1 0 D0–D15 contain variable 9
0 1 1 1 D0–D15 contain variable 10
The number you assign to a variable by setting strobe lines does not
necessarily correspond to the position of the variable in a message. The
DL40 expects to see all
[CTRL][V] variables numbered before [CTRL][W]
variables.
Triggering Rules example:
If a message has variables positioned as follows:
[CTRL][V] [CTRL][W] [CTRL][V] [CTRL][W] [CTRL][V]
First
Position
Second
Position
Third
Position
Fourth
Position
Fifth
Position
they must be numbered:
[CTRL][V] first position = Variable 1
[CTRL][V] third position = Variable 2
[CTRL][V] fifth position = Variable 3
[CTRL][W] Second and fourth position = Variable 4 (See NOTE below)
If the variables were not numbered as shown, they would be displayed in
wrong positions and possibly corrupted.
Note: [CTRL][V] variables always use a (16 bit) word;
[CTRL][W] variables do not use a full (16 bit) word.
•
If [CTRL][W] variables are ASCII (8 bit) variables, [CTRL][W] second
position would be sent in the high byte of Variable 4; fourth position
would be sent in the low byte of Variable 4.
•
If [CTRL][W] s are BCD (4 bit) variables, the [CTRL][W] in the second
position would be sent in the high nibble of the high byte of Variable 4;