The systems that have an alarm are the Fastbus crate, the Lecroy high voltage mainframe, the Camac crate controls VI, and the high voltage controls VI. Each one of these systems has an auditory alarm, and the Labview VI’s also have visual alarms. In the event of one these alarms going off, the person responsible for the system should be notified.

The only known case for the Fastbus crate to sound an alarm is when the power to the back panel of the crate was disconnect by the displacement of the safety bar, which run along the bottom of the modules. If the Fastbus does give an alarm, take note of the voltages and currents on the front panel by dialing through the digital display. Turn off the DC power by hitting the DC off button. The safety bar should be checked to see if it is resting properly, not allowing the modules to be pulled out. Turn the DC power back on and listen for an alarm. If none sounds, the Fastbus should be fine. If the alarm persists, repeat the steps above again. Andrei, Erik, and Edmundo should be called, and all action should be noted in the logbook.

The Lecroy high voltage mainframe may sound an alarm. If an alarm sounds, switch the key on the front panel of the mainframe to local. Press the HV Off button. If the alarm still sounds, toggle the power. If the alarm persists, there is a serious problem. Keep the power off. Review the manual, for any solutions to the problem. Cabling should be checked. The HV controls VI’s channel history needs to be inspected for any anomalies. Erik and Edmundo should be reached, and all information should be recorded. If the mainframe has a problem, all modules are to be moved into the same mainframe and the HV should be run from that unit.

The HV mainframe is controlled using a VI in Labview. This VI will give an auditory and visual alarm. This alarm is generated under three trip conditions, and each of them will disable the channel the trip occurred. The three conditions are a voltage hardware limit trip, a current limit trip, and an out of range limit trip. The hardware voltage limit is set on the rear of the high voltage module using a small common head screwdriver on a potentiometer. The measured threshold voltage is 1/100 of the limit voltage. The TOF modules are set to +900V. This trip occurs when the measured voltage is greater than the limit value, which usually occurs when the requested voltage is set too high. The current limit is a software limit, which is set during the initialization stages of the high voltage controls VI. This limit cannot be changed during the running of the VI, and the TOF tubes are set to 400 microAmps. This trip usually occurs when the tubes are being saturated with light. The out of range trip occurs when the measured voltage is +/- 5V out of range of the requested voltage. This is the most serious of the three since something is wrong either with the read out of the mainframe or something internal of the mainframe. The most common reason why this occurs is that a channel’s requested voltage is zero but is enabled. In this setting, some channels measure at most 10V, which will trip the channel. If the requested voltage is at zero, the channel should be disabled.

When the high voltage alarm trips, a large button will appear on the screen with a buzzing noise. The operator should press the button to acknowledge that the trip has occurred and should inspect the status display on the front panel of the high voltage controls. The color of the block, which represents a channel in the mainframe, will tell the operator why the channel was tripped. The channel’s history show be inspected using the information in the database, seen through the counting house portal on the web, and using the history plot on the front panel. The history plot on the front panel only displays the channel’s history over 24 hours, but with a greater resolution than what is written to the database. If the history of the channel looks normal until the trip, the cables to the mainframe should be checked. If there is access to the tunnel, the cables inside the tunnel should be inspected as well. If the PMT appears to be unharmed, that is to say that no odd changes in current of voltage were found, then the channel can be enabled again. The only way to enable the channel is by turning the HV off and then on. If the channel trips again without reason, then leave the channel off and further investigate the problem.

The final alarm is the Camac controls communication error warning that will appear on the same computer as the high voltage trip alarm. This warning occurs there is a problem in being able to communicate to the plastic Camac crates. The major reason for this occurring is that the crate is off. If the tunnel is open, check the status of the Camac crates, making sure that they are on and their status is OK. A good initial check to see if the alarm was only an anomaly is to press the "Read Out All Crates" button. If this operation performs correctly, then there is nothing to worry about.. To know that the operation performed properly, the X and Q values have to be valid , and the settings need to be other than a baseline value. For the TOF, these values have all channels unmasked, all the thresholds equal to 9mV, and the width is 0ns. The Camac crates should have continuous power to them since they are hooked up to a UPS each, whose information is displayed on the counting house portal on the web. Any problem with the UPS’s will be monitored through the silicon slow controls VI. If everything checks out OK, expect that the VI still producing an alarm. Restart the VI.

In the event of a fire or other event that might cost life, limb, or property damage, hit the Panic Off button on the high voltage mainframe. This will switch off the high voltage to all the channels instantaneously. Other systems might have to be turned as deemed necessary.