Mitsubishi Electric L02SCPU User's Manual And Reference page 240

(3) Standby screen
The standby screen is the initial screen of the display unit. The screen displays year, month, day, day of the week,
hour, minute, and second. The internal time of the CPU module is automatically read to the display unit. Pressing
any button moves you to the "function selection" screen.
*1 The
ESC
(4) Backlight
(a) Normal status
The backlight lights up green. (When any button is not pressed within set lighting period, the backlight will turn
off.) The backlight will turn on again in the following cases.
• Any button is pressed.
• A user message is popped up.
• An error is detected from the display unit by the self-diagnostic function.
*1 If this occurs, the backlight will not turn off even after elapse of set period.
(b) Error status
If an error occurs in the CPU module, the backlight lights up red. (When any button is not pressed within set
lighting period, the backlight will turn off.) Check error information in the "Error list" screen and clear the error.
( Page 259, Section 4.2.6)
Note that the backlight status does not change in the following cases.
• "0" has been set to each cause number setting area of LED display priority ranking (SD207 to SD209).
• The ERR. LED, USER LED, or BAT. LED of the CPU module does not turn on.
(5) Self-diagnostic function
When a display unit detects an error by self-diagnostics, a continuation error ("DISPLAY ERROR") occurs in the
CPU module, and an error message "DISPLAY UNIT ERROR" is displayed on the display unit. If the same error
occurs even after the CPU module is reset, the possible cause is a hardware failure of the CPU module or the
display unit. Check a 4-digit error code displayed on the display unit, and please consult your local Mitsubishi
representative.
238
button is invalid.
* 1
*1