Troubleshooting

Movement failure: automatic shutdown

If one of the 4 second-level microswitches (just after the first-level ones) is hit during the movement, the motor power supply will be turned off immediately. If this happens, a beeping sound will inform you that the motor movements are stopped and inhibited. To restore the operation,

1. Recognize the cause of the trouble (for example the MacA computer crashed), and try to fix it as much as possible (in the previous example restart the MacA and the slow control program);
2. Remove the inhibit; there is a switch in the left side of the $left$ rack; switch it in such a way as to turn off the corresponding light, then push the green button in the front of the $left$ rack, near the emergency button, in order to switch off the beeping sound. At the same time check that the motors are not moving (watch the 2 encoder displays in front of the $left$ rack);
3. Now you can move the motor only manually: switch on the 80 volts manual motor power supply (the switch is in front of Power Supply Module, at the bottom of $left$ rack);
4. Turn the remote/manual knob to manual position (the knob is in front of Motor Drive module, at the center of $left$ rack);
5. Select the direction, opposite to the one which caused the alarm (the switches are in front of Motor Drive Module);
6. Handle the joystick carefully, get ready to switch off the manual motor power supply if anything goes wrong.
7. As soon as the trouble has been fixed, restore the security, turning on the switch on the left side of the $left$ rack (the corresponding red light must be on). This is the same switch of step number 2. If you forget this step the security microswitches will be disabled and you risk serious damage to the movement system.

Emergency: Use of Movement System with the Cranks

If it is not possible, for any reason, to use the motors to move the target there is the chance of moving it manually, using some cranks. This procedure can be performed ONLY BY AUTHORIZED PERSONNEL, because of the RISKS TO THE TARGET. The procedure is the following:

• Remove the motors from their seats;
• Take the two cranks which are in the wooden box number 1, near the wall in Hall A;
• Mount the cranks instead of the motors;
• If the encoders are working, one can position the target by reading the encoder values on the display and matching the values with the look-up table which is in the manual;
• If encoders are not working, the alignment must be done by matching the signals on top of the scattering chamber.

Encoder substitution procedure

First of all, consider that the encoders are very delicate mechanisms, and must be carefully handled; please NEVER use hammers or similar tools unless you want to risk destroying them; moreover, do not apply torques directly on their axes, and turn them only by hand. For the substitution, execute the following procedure:

1. Switch the whole system off;
2. Remove the cable from the broken encoder;
3. Remove the cylindrical lead shielding which is around the encoder;
4. Remove the three screws at the base of the encoder, on the stainless steel ring;
5. Now you can remove the encoder.
   It has its stainless steel ring fixed on the base;
6. Remove this ring from the encoder, by unscrewing it;
7. Take the spare encoder from the wooden box number 1, near the wall;
8. Without remounting the encoder, you must realign the target to the reference position ^A2, by turning the top of the scattering chamber with your hands and aligning the reference point with the alignment signs on top of the scattering chamber; this can be done manually, after removing the motor corresponding to that movement. When you remove the vertical movement motor the target could drop down, which may severely damage the integrity of the target; for this reason you have to block the cog-wheels by putting something among the mechanisms before removing the motor. Be extremely careful when performing this procedure.
9. Now connect the new encoder to the cable, and turn on the power supply to the system. Check the value of the encoder position, which readout is displayed at the bottom of the left rack: this value must match with 27361 (rotation) or 17301 (up/down) ^A3. If values do not match, then turn MANUALLY the encoder axis, until the display value is at the desired one. When done, you can remount the encoder on top of the scattering chamber.
10. Switch off the system;
11. Put the stainless steel ring back on the encoder, as it was mounted before;
12. Re-check the encoder value, and realign it if it is changed;
13. On top of the scattering chamber, in the place where the encoder must be mounted, you will see two pairs of cog-wheels. Turn gently the two wheels of the upper pair, one CW the other CCW, in order to charge the small spring among them; then, keeping this spring in charge, position the encoder back on its place, and fix it by putting back its screws.
14. Connect the cable;
15. Check again the encoder value reading: if it is still 27361 (rotation) or 17301 (up/down) you are OK, otherwise you must remove the encoder and repeat the operations from the step 9. When the value is correct, you can remount the shielding;
16. Re-connect the cables;
17. Turn the system on;
18. Check if everything is OK, by moving the target up-down (and CW-CCW if rotation is enabled ) and watching the encoder reading values, which must change consequently: if everything is OK, then there is no need of a new calibration, and the system can work again; otherwise, you must understand which one of the above steps has failed, and go back to that starting point.

The water pump computer-control does not work

Check the following items:

• The switch above the MacB monitor must be in the ON position;
• The switch on the back of the MacB rack in the counting room must be in the REMOTE position;
• The pump speed switch in the front of the right rack in Hall A must be in the REMOTE position;
• The pump speed knob in the front of the right rack in Hall A must be at 60; notice that this knob should not be moved; it controls the maximum speed of the water pump. ^A4