5.3.3.18  Troubleshooting

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 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 the step number 2. If you forget this step the security microswitches will be disabled and you risk to seriously damage the movement system.

If it •s impossible, for any reason, to use the motors to move the target there is the chance to move it manually, using some crancks. This procedure can be performed ONLY BY AUTHORIZED PERSONNEL, because of the RISKS FOR THE TARGET . The procedure is the following:

• remove the motor from their seat;
• take the two crancks which are in the wooden box number 1, near the wall in HallA;
• mount the crancks 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.

First af 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 to destroy them; moreover, do not apply torques directly on their axes, and turn them only by hands For the substitution, execute the following items:

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, by turning the top of the scattering chamber with your hands and collimating 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; consider that if you remove the vertical movement motor the target risks to drop down, with severe risk for 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; so, be careful when performing this item

9

now connect the new encoder to the cable, turn the system on without turning on the motors, and check the value of the encoder position, by reading on the displays of the readout, at the bottom of left rack: this value must match with 27361 (rotation) or 17301 (up/down) . If values do not match, then turn MANUALLY the encoder axis, until the display value is the desired one. When done, you can remount the encoder on top of the scattering chamber

10

switch off the system

11

put back the stainless steel ring 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 wi ll see two pairs of cog-wheels; consider the upper pair; turn gently its two wheels, 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 everyting is OK, by moving the target up-down and CW- CCW 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 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 HallA must be in the REMOTE position;
• the pump speed knob in the front of the right rack in HallA must be at 60; notice that this knob should not be moved; it controls the maximum speed of the water pump;