Dayle Kotturi Lehman Review [email protected]. edu May 10-12, 2005 LCLS Timing Outline Scope SLC Master Pattern Generator Introducing the PNET VME receiver Status of the PNET VME receiver System diagram Timing pulse to pulse LCLS MPG Event Generator and Event Receiver Costs Conclusions
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Scope SLC Master Pattern GeneratorIntroducing the PNET VME receiver Status of the PNET VME receiverSystem diagramTiming pulse to pulseLCLS MPGEvent Generator and Event ReceiverCostsConclusions
LCLS timing system is used to transmit a fiducial 360 Hz signal to all triggered devices in LCLSSystem requirements (speed and content) are known: receive 128 bit PNET data at 360 Hz; append add’l info; operate at 120 HzThe component parts are known: PNET VME receiver, EVG-200 and EVR-200The interfaces are being defined
4 "one second’s worth” of PNET buffers are kept in 4 separate arrays
128 µs + several µs for speed of light travel
BGRP: PEPII
sends intr3 to MPG
saves PB2 to current full sec buffer
receives intr3
reads fault bits from camac
if BCS fault bit asserted, ISR sets BCSFAULT modifier bit in PB2 (created last intr)
finds which BGRP to execute
sends (modified) PB2
based on fault bits and BGRP var (from operator),find MGRP
execute MGRP which creates PB3
is interrupted by the arrival of PB2
xlate 5-bit base beamcode + modifier bits in PB2 into 8 bit beamcode and set up camac FC F19A10 so that “2/360s early” cmds in PB2 will happen next fiducial
set up camac FC F19A9 so that “1/360s early” cmds from PB1 will happen next fiducial
set up camac FC F19A8 so that “on time” cmds from PB0 will execute next fiducial
looks for YY=243. If found, mark current full sec buffer not to be overwritten OR if full, mark next
if BCS fault bit asserted, ISR sets BCSFAULT modifier bit in PB3 (created last intr)
finds which BGRP to execute
sends (modified) PB3
based on fault bits and BGRP var (from operator),find MGRP
execute MGRP which creates PB4
is interrupted by the arrival of PB3
xlate 5-bit base beamcode + modifier bits in PB3 into 8 bit beamcode and set up camac FC F19A10 so that “2/360s early” cmds in PB3 will happen next fiducial
set up camac FC F19A9 so that “1/360s early” cmds from PB2 will happen next fiducial
set up camac FC F19A8 so that “on time” cmds from PB1 will execute next fiducial
looks for YY=243. If found, mark current full sec buffer not to be overwritten OR if full, mark next