Editing Variables With The Td; Acknowledging And Editing A Message; D.6 Editing Variables With The Td 200 - Siemens SIMATIC TD 200 User Manual

TD 200 Parameters and Messages
D.6

Editing Variables with the TD 200

You can use the TD 200 to modify variables embedded in the messages. You can also
configure a message to require that an operator acknowledge the message (see
Section D.5). Messages that must be acknowledged flash when displayed on the TD 200.
The operator uses the arrow keys and the ENTER key to acknowledge messages and to edit
variables.
Note
Due to restrictions in the format used to store real (floating-point) numbers in both the
S7-200 CPU and the TD 200, the accuracy of the number is limited to six significant digits.
Editing a real number with more than six digits may not change the value of the variable, or
may cause other digits within the number to change:
Changing the least significant (right-most) digit of a real-number variable with more
than six digits may have no effect. For example: if you try to change the "9" in
"1234.56789", the value of the variable does not change.
Changing the most significant (left-most) digit of a real-number variable with more than
six digits may cause other (less significant) digits in the variable to change.

Acknowledging and Editing a Message

Use the following procedure to edit a variable:
1. If the message does not require acknowledgement (is not flashing), select the message
by pressing either the UP or the DOWN arrow key to place the cursor on the first
character of the desired message.
2. Press ENTER to move the cursor to the least significant (right-most) character of the first
editable variable.
For messages that require acknowledgement, pressing ENTER also sets the
acknowledge-notification bit in the CPU and halts the flashing of the message on the
display.
3. If the variable is password-protected, enter the 4-digit password at the prompt and press
ENTER.
4. Press either the UP or the DOWN arrow key to increment or decrement the variable.
(Pressing and holding either the UP or the DOWN key accelerates the increment or
decrement operation.)
– To move the cursor to the next digit position, press either the SHIFT UP (left) or the
SHIFT DOWN (right) keys.
– To reset the variable to 0, press the SHIFT ENTER keys.
5. Press ENTER to write the updated variable to the CPU.
On the same program scan, the edit-notification bit is set in the format word
corresponding to the variable being edited.
D-22
SIMATIC TD 200 Operator Interface
C79000-G7076-C205-04