Editing A Value - Siemens SIMATIC TD 200 User Manual

Editing a Value

You can use the TD 200 to modify variables embedded in the messages. The operator uses
the arrow keys and the ENTER key to select a message and to edit variables.
Use the following procedure to edit a variable:
1. Select a 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 in the message.
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.
At the same time the updated value is written to the CPU, the corresponding
edit-notification bit is set to 1.
If you do not edit the message variable, or abort the edit by pressing ESC, the
message-enable bit is not cleared by the TD 200. The message-enable bit is cleared by the
TD 200 only when you write the last editable variable to the CPU.
The UP and DOWN arrows that indicate higher and lower priority messages, if any are
present, are disabled while an edit is in progress. These functions are restored when the edit
is completed or aborted.
If there are more editable variables in the message, the cursor moves to the next variable.
After all of the variables in the message have been edited, the message-enable bit for the
message is cleared in the CPU. The message is then removed from the display on the next
update cycle.
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.
You can abort an edit at any time by pressing ESC. This causes the TD 200 to reread the
message from the CPU and to display the variables from the CPU. When the edit session is
aborted, any values that have already been sent to the CPU (by pressing the ENTER key
after modifying the value) are displayed; any value that was modified but not saved is
overwritten by the previous (original) value.
SIMATIC TD 200 Operator Interface
C79000-G7076-C205-04
Operating the TD 200
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