- The input for engine rotation is allowed to open. This activates the setpoints.
- The setpoints are armed when the temperature rises to the programmed value.
- The start-up timer is activated.
- The start-up timer expires and all of the alarms are armed.
Each condition must be met before the next condition occurs. If the achieved status of any prior condition is lost, the sequence will restart from that condition.
Not all of the alarms require all three steps in order to be armed. Table 1 lists the alarms and the conditions that are programmed at the factory for arming of the alarms. For more information on the alarms, refer to Systems Operation, "Setpoints" and Systems Operation, "Alarm Description".
| Alarms and Default Conditions for Arming of the Alarms | |
| Alarm | Condition |
| "CYL DEV" | The circuit for the input for engine rotation is open. The temperature for arming of the parameters is achieved. The start-up timer has expired. |
| "CYL HI 1" | |
| "CYL HI 2" | |
| "TO HI 1" | The circuit for the input for engine rotation is open. |
| "TO HI 2" | |
| "TI HI" | |
Note: Any alarm can be configured to be armed by the input for engine rotation only. Any alarm can also be configured to be armed by all of the conditions. However, custom wiring, a computer, and the proper software are required. For more information, consult the appropriate Caterpillar Engine Customer Service.
Input for Engine Rotation - It is important for the circuit of this input to be open during normal engine operation. When the circuit is open, the scanner can activate alarms.
When the circuit is grounded, all the alarms are deactivated and the engine is not protected against problems with exhaust temperatures.
It is not necessary to connect the circuit for input of engine rotation. The circuit is left open by the factory.
Note: The arming temperature and the start-up timer are adjusted with the "SETPTS" menu. Refer to Systems Operation, "System Configuration Parameters".
Arming Temperature - To arm the alarms, the average cylinder temperature must rise above the arming temperature. This temperature can be reprogrammed with the keypad.
The average cylinder temperature must stay above the arming temperature during normal operation. If the average cylinder temperature becomes less than the arming temperature, the alarms that depend on the arming temperature are deactivated.
Start-up Timer - The start-up timer starts when the arming temperature is achieved. When the start-up timer is running, the display shows the time in minutes and in seconds until the timer expires. The display shows "TIMER", "xxm", and "xxs".
If no alarms are configured to use the timer, the screen for the start-up timer is not displayed during start-up of the scanner.
For arming of the selected alarms, the average cylinder temperature must stay above the arming temperature until the timer expires. Otherwise, the timer restarts.
| "ENTER/ACK" key |
To cancel the start-up timer, press the "ENTER/ACK" key.
| "RESET" key |
To reset the timer to the full amount of programmed time, press the "RESET" key.
| "ESC" key |
| Up Arrow and Down Arrow keys |
To display the normal screen during operation of the timer, press the "ESC" key or press one of the arrow keys. To return to the screen for the start-up timer, press the "ESC" key again.