Troubleshooting: Data Comes Slowly

This is most likely to be a problem with the electronics setup, cabling or failure. Note that, if data is missing from one or more readout boards, the synchronization box will eventually generate a time out and allow the next trigger. Common problems include:

• Slow trigger rate: Verify that raw triggers come at a reasonable rate from the trigger source - the clock for pedestal and pulser runs.

• Wrong Rosie-busy configuration: Verify that the synchronization module setup is correct, with Rosie busies enabled (switch up) if, and only if, the Rosie was enabled at configuration time.

• No data from an RDO: Check the MiniDAQ i960 windows for error messages that indicate Rosie errors due to link problems or missing/corrupt data; also, check the Rosie LED's.

  • Link problems:

    • FEE power supplies must be on and properly connected for all enabled readout boards.

    • Optical fibers must be undamaged and properly connected; diagnose by swapping fibers or checking the laser power output from the suspect fiber with a meter.

    • Readout boards lasers sometimes fail to couple enough power to the optical fiber for a proper connection due to RDO voltage regulation, laser failure or laser mis-alignment; this usually requires a repair by Fred Bieser.

    • A Rosie failure can cause a link problem, but this is rare.

  • No trigger to an RDO: RDO's have a green LED that flashes visibly for each trigger; if it doesn't, check the trigger cable connections.

  • No RDO data following a trigger: If an RDO repeated fails to transmit an event after being triggered, the readout board usually requires repair, but occasional misses (a few times per day, or less) are usually impractical to debug.

• Corrupt data: If an RDO repeatedly supplies corrupt/wrong-length data buffers or headers - the RDO, the link or the Rosie requires repair.

Page maintenance:

Roy Bossingham, LBNL
RRBossingham@lbl.gov