Hall-C ROC3 Current Trip

ROC3 Current Alarm

Failure Modes

• There are 2 typical failure modes that indicate there are either issues with HMS data observed via the online replays or ROC3 is in a failed state

If ROC3 is in a failed state

1. The alarm handler will sound for ALARM: hccrate03:CurrentRead:u0
   • In this instance the current draw will have exceeded 60A and the crate will be required to be power cycled
   • Refer to this log entry for an example of the alarm handler in an active state
2. The online monitoring replay will produce multiple errors. The following example is a the typical set of errors that may be returned during the online replay when ROC3 has exceeded its current draw trip set point

TDC1190 Error: Slot 4, Chip 0, Flags 4000 , Ev #0
TDC1190 Error: Slot 4, Chip 1, Flags 4000 , Ev #0
TDC1190 Error: Slot 4, Chip 2, Flags 4000 , Ev #0
TDC1190 Error: Slot 4, Chip 3, Flags 4000 , Ev #0
TDC1190 Error: Slot 5, Chip 2, Flags 4000 , Ev #0
TDC1190 Error: Slot 7, Chip 0, Flags 4000 , Ev #0
TDC1190 Error: Slot 7, Chip 1, Flags 4000 , Ev #0
TDC1190 Error: Slot 7, Chip 2, Flags 4000 , Ev #0
TDC1190 Error: Slot 7, Chip 3, Flags 4000 , Ev #0
TDC1190 Error: Slot 8, Chip 0, Flags 4000 , Ev #0
TDC1190 Error: Slot 8, Chip 2, Flags 4000 , Ev #0

• If the ROC3 current alarm sounds or the online replay threw errors, the following steps should be taken to recover the DAQ

1. Kill all CODA processes with the command kcoda
2. Power cycle ROC3
   • Follow the steps on this link
   • If the power cycle was effective then the current read back in the alarm handler variable ALARM: hccrate03:CurrentRead:u0 should be reading ~58 A
   • Do not proceed if the alarm handler is still alarming. If it is, try power cycling the crate again.
3. Start CODA processes with the command startcoda
4. Take a new run and immediately replay and look for more 1190 errors

The Drift Chambers are Oscillating

• The HMS drift chambers are ringing and clobbering the TDC's which are readout via ROC3
• The online monitoring replay will produce multiple errors. The following examples are two possible sets of errors that may be returned during the online replays

1. TDC1190 Flag 1000 errors

TDC1190 Error: Slot 7, Chip 0, Flags 1000 , Ev #0
TDC1190 Error: Slot 7, Chip 1, Flags 1000 , Ev #0
TDC1190 Error: Slot 8, Chip 0, Flags 1000 , Ev #0
TDC1190 Error: Slot 8, Chip 1, Flags 1000 , Ev #0
TDC1190 Error: Slot 8, Chip 3, Flags 1000 , Ev #0
TDC1190 Error: Slot 10, Chip 0, Flags 1000 , Ev #0
TDC1190 Error: Slot 10, Chip 1, Flags 1000 , Ev #0

1. TDC1190 Flag XXX errors

TDC1190 Error: Slot 2, Chip 0, Flags 249 , Ev #4987 
TDC1190 Error: Slot 2, Chip 2, Flags 259 , Ev #4987
TDC1190 Error: Slot 4, Chip 0, Flags 2c9 , Ev #4987
TDC1190 Error: Slot 5, Chip 1, Flags 2d9 , Ev #4987
TDC1190 Error: Slot 5, Chip 2, Flags 6c9 , Ev #4987
TDC1190 Error: Slot 7, Chip 0, Flags 259 , Ev #4987
TDC1190 Error: Slot 7, Chip 1, Flags 64b , Ev #4987
TDC1190 Error: Slot 8, Chip 0, Flags 249 , Ev #4987
TDC1190 Error: Slot 8, Chip 3, Flags 249 , Ev #4987

• In order to get the chambers back into a stable state the threshold will need to be raised to a large value for ~1 min and then reduced to the nominal operating value.
• To bring up the threshold GUI follow the following steps

1. Open a terminal and type the command jmenu
2. In the search bar type threshold and hit enter
3. Under the Screens list select HallC Drift Chamber Thresholds
4. In the HMS Set field enter 20.0
   • The read back voltage with saturate at ~18 V, wait ~1 min and then lower the threshold back to the nominal value 5.5 V
5. If the ROC3 over current alarm has not not been activated then take data and perform an immediate replay. If there are no errors thrown then carefully look at the monitoring histograms. If no anomalies are present, then the data should be good.