Edit-Notification Bit 2 - Siemens SIMATIC TD 200 User Manual

You can design your S7-200 program to take other actions as a result of setting the
acknowledge-notification bit. Figure D-13 shows how you can use the
acknowledge-notification bit. For this example, VB21 is assumed to be the most
significant byte of the first format word of the message.
Ladder Logic
Network #
V21.1
. . .
Figure D-13 Sample Program for Using the Acknowledge-Notification Bit

Edit-Notification Bit 2

The TD 200 sets the edit-notification bit to 1 after an edit. The CPU can read this
edit-notification bit value to recognize when an editable data value has been
changed. The program can then read and make use of the edited value.
Note
The edit-notification bit does not reset automatically when subsequent edits are
performed. If you want the TD 200 to detect and notify you of a second edit
operation, you must design your program to reset the edit-notification bit to zero.
Figure D-14 shows the placement of the edit-notification bit, located in byte 0 of
the format word.
MSB
Figure D-14 Edit-Notification Bit of Byte 0 of the Format Word
SIMATIC TD 200 Operator Interface
C79000-G7076-C272-01
V21.1 1
R
LD
R
MOV_B
MOVB . . .
EN
IN OUT
. . .
Format Word
Byte 0 Byte 1
MSB of LSB of
Format Format
LSB
7 6 5 4 3 2 1 0
0 0 E P EN AN A
TD 200 Parameters and Messages
Statement List
// Resetting the acknowledge-notification
// bit and using it to enable the next
// message
V21.1 // When the operator acknowledges the
V21.1,1 // message, reset the bit and enable
// the next message
// Move ...
Optional Data Value
Byte 2 Byte 3 Byte 4
MSB of
Data
EN- Edit-Notification
0 - Not edited
1 - Message edited
Byte 5
LSB of
Data
D-15