Control and operation

Operating the excavator in safety modes

Diesel engine RPM adjustment in safety mode

In normal operation, the desired value for the engine RPM is entered via the buttons S86, S228 and S229, and the engine speed is controlled in consequence by the electronic system of the machine.

If the engine has been started in safety mode via the rocker switch S71 so it can be operated only with two different RPM values. The commutation between the two values is achieved via the switch S72.

Manually choose one of the values:

•with the switch S72 tilted to the left, the engine runs at the lower safety RPM.

•with the switch S72 tilted to the right, the engine runs at the upper safety RPM..

Notice !

When the engine is switched automatically into safety operation, the current engine speed is maintained as long as the engine is not shutdown.

Safety operation of the servo control circuits

During normal operation, the servo pressure supply to the swing brake and to the joysticks and pedals is controlled over the electronic circuit of the machine. While tilting the switch S73 in safety position, this servo pressure supply can be enforced, and is maintained even in case of a trouble in the normal control circuit.

Tilt copyright by

Commute the switch S73 into safety position (tilt to the right). the three indicator symbols S73a, S73b and S73c appear on the display. the joysticks and pedals are supplied with servo pressure. the swing brake is released.

Danger!

The safety mode must be turned on only temporarily and in order to move the machine for emergency reasons and when, due to a trouble in the normal control circuit, releasing the swing brake or supplying the pilot controls is hindered. In safety mode, the swing brake will be released as soon as the ignition key is turned to contact position, and the normal brake control is out of function.

Inform all personnel involved in the operation or maintenance of the machine that the safety mode has been turned on and that, by the fact, the control of the swing brake is modified.

Locate the trouble which makes the operation in safety mode necessary and get it repaired as quickly as possible.

Note !

Even with the switch S73 in safety position, the servo pressure supplying the joysticks and pedals is interrupted when tilting up the safety lever .

3.5.2Safety operation of the main working pumps

During normal operation of the excavator, the electronic horsepower control continuously adjusts the pumps flow to the pressure level of the working circuits If a trouble occurs in the circuit of the regulator, the pumps are swivelled back to minimal flow.

However, it remains possible in this case to carry on the working with the machine (with somewhat reduced pump power) by changing over the lever 3 on the servo oil unit which is mounted to the rear face of the spool valve console.

Switching the main pumps in safety operation

Change over the lever 3 on the servo oil unit which is mounted to the rear of the hydraulic tank:

–Disconnect the connector 1 from the regulation solenoid valve Y50. –pull out the pin 2 –tilt the lever 3 in horizontal position (safety position). the safety operation of the main working pumps is turned on.

3.5.3Emergency attachment lowering with defective servo circuit

In case of a trouble in the electronic servo control circuit (defective joystick, electronic plate, regulation solenoid valve, ...) the working attachment can be lowered, in case of a necessity, thanks to the push button S42 situated on the left control desk.

The emergency lowering via S42 is possible only if the servo control circuit is under pressure. If necessary, start the Diesel engine to allow the servo-pressure to establish.

Fig. 3-95 Emergency lowering of the attachment

Perform emergency lowering procedure as follows: turn the ignition key to contact position tilt up the protective cover of the push button. press down the push button and keep it depressed. the working attachment lowers due to its own weight. release the push button as soon as the attachment has reached the desired position.

Preselection of emergency lowering movements (Option)

On some types of working attachments it is advaisable to have the possibility to actuate the downward movements separately for the different attachment parts. This allows to bring the special working attachment in its safety position, down to the ground level.

The 3-positions preselection switch S41 on the rear right control desk allows to select the attachment part to be emergency lowered.

Hinweis

For the machines fitted with a demolition attachment or with an industrial attachment, the following chart gives the correspondances between the positions of the preselection switch S41 and the resulting downward movements The label sticked on to the side window of the cab also indicates these correspondances.

3.5.4Emergency supply of the boom cylinders (option)

With this option, an external pressure source can be used to supply the boom cylinders with oil. In case of engine or hydraulic system failure, the working attachment can be raised or lowered.

Caution!

Risk of irreparable damage to the hydraulic system!

Make sure that the oil supplied by the external source matches the following conditions:

•the oil corresponds to the hydraulic oil specifications in this manual

See chapter 5: "Hydraulic oil",

•the oil is miscible with the oil in the hydraulic system of the machine,

•the percentage of purity corresponds at least to the that of the oil in the hydraulic system of the machine (10 – 20 µm filtering).