Minutes of the 9th Timing Working Group Meeting (TimWG)
Held on Friday the 27th August 1999

Present:

Pal ANDERSSEN, Philippe BAUDRENGHIEN, Gary BEETHAM, Etienne CARLIER, Michel JONKER, Mike LAMONT, Quentin KING, John PETT, Jean-Jacques SAVIOZ, Javier SERRANO.

Excused:

Adriaan RIJLLART, Julian LEWIS.

Agenda

Approval of previous minutes

There were no corrections on the previous minutes.

Computer synchronization

Pal ANDERSEN presented a computer synchronization mechanism based on NTP (Network Time Protocol): "timekeeping among distributed clients and servers". This protocol is based on the calculation of the rountrip delay and the clock offset between host and peer, and permits the correction of small time drift between computers. The protocol takes into account the network traffic and distance between NTP client and server. This product is available for HP-UX. The availability for LynxOS platforms has to be checked.

LHC slow timing requirements for machine operation

Michel JONKER presented the LHC slow timing requirements for operation (see slide attached). He outlined the different possible modes of operation (Idle and preparation, Filling, Ramp, Physics preparation, Stable beam, Dump and post mortem analysis) and reviewed what can be learned from LEP operation. For each mode of operation, he identified the different timing functionality (scheduled timing events to control equipment, sequenced actions, concurrent usage of asynchronous trims and real time parameter knobs, message sequencing, inter-equipment synchronization...) necessary for an optimum operation.

AOB

Philippe BAUDRENGHIEN updated the different slow and fast timing requirements for the SL/HRF group. He raised up  the question of fast analog PU signals from transfer lines to the RF faraday cages (BA3 & LHC point 4) for fast timing adjustment and synchronization control.  He proposed that SL/HRF provides fast timing signals to the PCR and that users should then get them from the PCR. Finally, he reminded that optical fibers already exist between PCR and SR4 / LEP RF pits.

Next meeting

Next Meeting will be held on Friday 24 September 1999 at 10:00 AM in 864 1C01.

Agenda

1. Approval of previous minutes
2. Fast timing distribution through fiber optics. Bruce TAYLOR
3. Preliminary discussion on report to PLC. Gary BEETHAM
4. Next speakers & next meeting
5. AOB