Siemens simatic PC 577 Operating Instructions Manual page 89

Function keys and softkeys
The softkeys are arranged on the left and on the right, and the function keys in a double row
below the display.
Figure 8-2
Control keys
The control keys activate editing functions and control functions in different applications:
Alphanumeric keys
Enter letters, special characters, blank spaces and underline using the alphanumeric keys.
SIMATIC Panel PC 577
Operating Instructions, Release 04/2006, A5E00798484-01
Function keys and softkeys
8.2 Operator controls on key panels
1 Backspace
2 Open Help
3 Toggling between the pre-defined key
assignment and special characters,
arithmetic symbols and signs
4 Acknowledge
1 Underline
2 Blank
Operating
8-5