24 Preliminary
PTS 916 Cd
3.3.3 A closer look at some operating
procedure blocks
Process information
While the compressor is running, the operator can take a brief look
at all the incoming compressor and engine data, by pressing the
Process Info button.
This can be very useful for troubleshooting over the phone.
System information
When in the Ready for Start status the System Info button is
pressed, all the system configuration settings are displayed, such
as: unit type, max. and min. set pressure, active control mode, max.
set RPM, battery voltage.
From here the operator can enter the Options status, where he can
configure all the parameters he has access to.
Options
Here the screen shows all the parameters the operator can edit.
With the arrow buttons, one scrolls to an object, and toggles or
selects it with the right function button.
Selected values can be changed with the arrow buttons, and the new
value is confirmed with the OK button.
At any time the operator can leave the Options status and go to the
Ready for Start status by pressing the Return button.
Cranking procedure
When a start request is made, either by the operator or
automaticaly, the horn and flasher light outputs are activated for the
duration of the start warning time.
All the compressor parameters are checked.
When one of these parameters is out of its limits, the operator is
prompted to the Start failure status, and must return to the Ready
for Start status or to the System Info status.
When all the parameters are within limits, the engine starts
cranking.
The starter motor runs for a preset time, and then the engine rests
for some time, before trying to start again.
This cycle is repeated for a number of times.
When the engine does not start, the starting procedure is ended, and
the operator is prompted to the Start Failure status after several
failed attempts.
When during the cranking procedure the operator presses the Stop
button, a stopping procedure will be executed, and the compressor
will return to the Ready for Start status.
Warming up
When the engine starts, the compressor enters the Warmup status.
This means the engine is going to run idle until the engine coolant
temperature has reached a specific value. If this coolant
temperature setting is already reached, there is no warmup, and
loading can immediately commence.
When after a specified maximum time the coolant temperature
setting is not reached, the compressor will proceed anyway.
When starting manually, the operator can press the Auto Load
button. This will result in a skipping of the Not Loaded status, and
loading directly after the Warmup status.
Pressure regulating system
A PID regulating system is implemented in the CCM and becomes
active in the Load/Unload status. This PID regulates the air
discharge pressure by adjusting the engine RPM between RPM
Min. and RPM Max.
When the air discharge pressure, which is monitored, drops below
the Reload pressure, the loading valve is opened and the PID
becomes active (load condition).
When less air is needed, the pressure rises and the PID will
decrease the engine RPM.
When the engine RPM is at its minimum, and the air flow needed
is still smaller than the compressor’s output, the pressure will rise
until it reaches the Unload pressure. Then the PID will become
inactive and the loading valve will close. The engine runs at RPM
Min. (unload condition).
When the air discharge pressure drops again, below the Reload
pressure, the loading valve is opened and the PID becomes active.
Cooling down
When the Stop button is pressed, the engine runs idle for a specified
time. If the engine already ran unloaded for some time, before
pressing the Stop button, this time is substracted from the cooldown
time because the engine conditions in these cases are the same. This
is also why the engine stops without cooldown in automatic stop
operation.
When a unit goes to cooldown due to "Engine coolant temperature
too high" (see “Engine warnings”). The unit will shut down and on
the screen appears "ready for start". When pressing the start button
"start request denied" will be displayed. After resetting, this
message is cleared and a start attempt can be made. Cooldown
Time: default 3 minutes.
Shutdowns
There are several parameters which are continuously watched.
When one of these parameters exceeds the specified limits, the
compressor will shutdown immediately.
The parameters appear on the screen.
The operator can leave the Shutdown status at any time, and go to
the Ready for Start status or to the Process Info status by pressing
the reset button.
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