Real-Time Data Transfer using the Timing System

1
Real-Time Data Transferusing the Timing System

• (Original slides and driver code by Babak
  Kalantari)

2
Key Hardware Features

• Event rate max 125 MHz
• 8 bit event code 8 bit signals or data
  (multiplexed)
• Real-time data transfer rate max 62.5 Mbytes/sec
• At 1kHz linac repetition rate60 kBytes/bunch

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Event System Overview
8 bit data
8 bit event
8 bit signals
8 bit event
Event Receiver
Event Receiver
Event Stream
Timing IOC
FO links
Event Generator
ext. signals
Fan out
50Hz mains
Event Receiver

• local delays
• programmable pulses
• on/off signals
• real-time data

Ref. clock master osc.
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Sources of Real-Time Data

• Master timing IOC real-time
• Other IOC network latency but synchronous
• Upstream via timing system real-time

IOC1
Event Receiver
Network
IOC2
Event Receiver
Event Receiver
IOC3
Timing IOC
IOC4
Event Receiver
Event Generator
Event Receiver
Fan out
Event Receiver
FO links
IOCn
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Driver Software

• Real-time data is seen as buffer of 2048 bytes
• Variables can be mapped to offsets
• Event generator and receivers have to agree on
  mapping
• Send buffer on write or on trigger
• Interrupt on buffer receive
• Configuration in startup script
• mrfDBuffConfigure ("device", cardno, eg)
• Still some work to do
• Endian issues
• Scheduling

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Device Support

• Generic device support for blocks of registers
• Originally designed for S7 PLC communication over
  ethernet
• Supports all standard i/o record types and data
  types
• Process input records "I/O Intr" (with high
  priority)
• Examplerecord (ai, "(NAME)") field (DTYP,
  "regDev") field (INP, "_at_evr/16 TFLOAT") field
  (SCAN, "I/O Intr") field (PRIO, "HIGH") field
  (PREC, "6"

device name
data type
offset in bytes
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Example Real-Time Data

• Bunch train counter
• 32 bit int
• double (52 bit mantissa)
• 3 day test shows 100 reliability
• Other beam parameters
• bunch train length, energy,
• With upstream data measured parameters
• intensity, position,

overflow in 16 months (at 100 Hz)
good for 1.4 million years
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Application Synchronization

• (e.g. synchronous camera and current monitor
  trigger)
• Application sends code to timing master
• Event system distributes application code
• IOCs arm devices depending on code
• Devices acquire data synchronously

Exp. 3
Exp. 2
dev. 1
dev. 3
Beam source
Exp. 1
dev. 2
dev. 4
Exp. 4