Maintenance
5-17
User Guide Rel 1.0 Standard May 1999
Procedure 5-7
Starting up the ECU
Use this procedure to verify the environmental control unit (ECU) start up
sequence. The ECU has a start up and initialization routine which begins if any
of the following three procedures are performed:
• The reset switch is pressed, which is located next to the heat exchanger
(HX) fan 1 LED on the front panel. This will cause a restart.
• The software locks up and the watchdog timer (WDT) times out and forces
a reset and a restart.
• When power is first applied, the power on reset causes a reset and start up
begins.
During start up, the processor begins an initialization procedure to control all
ECU functions (see Figure 5-12) and steps below.
Action
Step Action
1
Check that the following start up occurs in sequence.
2
Check that all LEDs will first light red.
3
Check that all LEDs will light green.
4
Check that all LEDs will turn off.
5
Check that all LEDs will cycle one at a time to indicate individual control.
6
Check that all LEDs will light in a chasing sequence, first green and then red.
7
Check the LED array will display a green led to indicate an on dip switch.
8
Check the LED array will not light to indicate an off dip switch.
Note 1:
While the ECU is displaying the dip switch sequence, all fans that are
enabled will cycle on and off.
Note 2:
After all fans are turned off, the ECU will enter the main control loop
and begin operating based on temperature.
—end—
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