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.
SIMATIC TD 200 Operator Interface
C79000-G7076-C272-01
Operating the TD 200
3-3