How to reset a Not-Aus button:

There are two different types of Not-Aus buttons, those ones within the experimental area (so called MKI Not-Aus) and the rest. The "Not-Aus experiment" is somewhat special because it has a twofold function:
It allows you to switch off all electrical power within the experimental area (as the other Not-Aus buttons) and it stops HERA and dumps both beams, in case you are still in the experimental area and HERA starts to inject.
As a result, the "Not-Aus experiment" requires two different reset buttons [a) and b)], whereas in all other cases you just have to reset the SPS by procedure b). Before resetting the control electronics, you have to unlock the button itself by turning it.
It is obvious that a "Not-Aus button" must be reset only if you are absolutely sure that the dangerous situation that forced somebody to hit the Not-Aus is not persistent anymore.

a) Not-Aus experiment:

Take the keys which are required to set up the interlock (key box in control room), go to room 501, open rack 22, the uppermost crate and press the reset button in a unit called "Experiment HERA-B" (see Fig. 1). If this is done continue with b).

b) All other Not-Aus buttons:

There are two control panels labeled "HERA-B Experimentesicherheit" (control room, 1st rack near the entrance door (see Fig. 2) or room 201, 2nd rack on the right), where you find a push-button labeled "Reset Not-Aus". These push-buttons are illuminated in case a Not-Aus has been set.
In order to reset you just have to press one of these push-buttons.

Now you can switch on the corresponding power distribution frames. The big red switch has to be grounded (green 0) and then switched on which requires some effort.
If case a), all the electrical power was switched off. You have to switch on the three power distribution frames HV10, HV11 and HV12. Then you can switch on the three distribution frames in the three floors of the trailer. For details have a look at the power distribution scheme .

  Fig. 1

  Fig. 2

Edited by J. Spengler, latest update 05/11/99