From logical to physical architecture

1
From logical to physical architecture

• The following slides uses the example of RT-knobs
  to study the transition of logical to physical
  architecture.

2
Real time knobs some reflections on rt knobs

• Real time knobs fit in perfectly in an rt control
  architecture.
• If an rt-knob is controlled by an rt measurment,
  we have an rt-feedback system.
• Here they are used to study possible physical
  architectures.
• How are they defined and how do they work
• What do they have in common with other RT control
  such as feedback.
• What is needed to control them
• What are the physical architectural issues

3
Real time knobs

• Definition of a knob (real time or software)
• a parameter that is linked to a set of equipment
  with some precisely defined knob-functions to
  modify the setting of the equipment
• EquipValuen Knob.Functionn(Knob.value)
• Examples
• IQF(t) IRefQF(t) DeltaIQF
  QhKnob.value
• IQF(t) IRefQF(t) IRefQF(t) deltaIQF
  QhKnob.value
• The Knob Function may include other reference
  parameters as well
• IQF(t) IRefQF(t) EnergyRef(t) DeltaIQF
  QhKnob.value
• To use a knob with a Knob Function that include
  reference values on a device while the reference
  functions are changing (I.e. during a ramp)
  requires that the knob converters know the
  reference functions and that they are
  synchronised with the equipment.

4
RT-knobs Logical Connection diagram
RTdev-1
RTdev-2
RTdev-3
Knob D
Knob C
Knob B
Knob A
Function A-1
Function A-2
Function A-3
Function B-2
Function B-3
Function B-4
Function C-1
Function C-5
Function D-6
Function D-99
Sum-1
Sum-2
Sum-3
Sum-4
Sum-5
Device-1
Device-2
Device-3
Device-4
Device-5
Device-6
Device-99
5
Real time knobs

• Observations
• A single knob can be linked to more than one
  equipment.
• More than on knob can be linked to the same
  equipment.
• The knob function can be expressed as a function
  of the knob variable, and any of the equipment
  reference variable (provided that they can be
  made known to the knob-converter)
• The knob functions do not have a rigid
  definition, their definition can be modified when
  needed.
• Real time knobs are made from knobs by linking
  the knob value to a real-time output device
  (operator console, q-measurement feedback)

6
RT-knobs implementation 1,Central knob
processing
RTdev-1
RTdev-2
RTdev-3
Knob D
Knob C
Knob B
Knob A
Function A-1
Function A-2
Function A-3
Function B-2
Function B-3
Function B-4
Function C-1
Function C-5
Function D-6
Function D-99
Sum-1
Sum-2
Sum-3
Sum-4
Sum-5
Device-1
Device-2
Device-3
Device-4
Device-5
Device-6
Device-99
7
RT-knobs implementation 1,Central knob
processing

• Description
• RT output devices send RTknob values to a central
  RTknob process
• The RTknob process sends one correction value
  message for every knob update to the involved
  devices.
• Multiple knob updates in the same slot are
  combined
• The RTknob process may also broadcast correction
  values even if nothing changed
• Since the summing is done centrally, the knob
  processing is best performed centrally.
• RT output devices have to communicate with the
  central RTknob process.
• The central RTknob process may take into account
  dependencies between knobs values (cross terms
  EquipValue function(knob.A, knob.B) )
• Bandwidth usage
• Nknobs knob-update-frequency
• Ndevices knob-update-frequency

8
RT-knobs implementation 2summing by the devices
RTdev-1
RTdev-2
RTdev-3
Knob D
Knob C
Knob B
Knob A
Function A-1
Function A-2
Function A-3
Function B-2
Function B-3
Function B-4
Function C-1
Function C-5
Function D-6
Function D-99
Sum-1
Sum-2
Sum-3
Sum-4
Sum-5
Device-1
Device-2
Device-3
Device-4
Device-5
Device-6
Device-99
9
RT-knobs implementation 2summing by the devices

• Description
• RT output devices send RTknob values to a
  dedicated RTknob process
• The RTknob process sends one correction value
  message for every knob update to the involved
  devices.
• Multiple knob updates in the same slot are
  combined
• The RTknob process may also broadcast correction
  values even if nothing changed
• The summing of the knob corrections is done on
  the device
• Since the summing is on the device, the knob
  processing may be distributed.
• RT output devices may include the RTknob process
• Dependencies between knobs values (cross terms)
  can only be managed if the knobs are handled by
  the same RTknob process.
• Bandwidth usage
• Number of knobs knob-update-frequency
• ?(Ndevices/knob knob-update-frequency)
  (summed over all the knobs)

10
RT-knobs implementation 3knob functions in the
devices
RTdev-1
RTdev-2
RTdev-3
Knob D
Knob C
Knob B
Knob A
Function A-6
Function A-99
Function A-1
Function A-2
Function A-3
Function B-2
Function B-3
Function B-4
Function C-1
Function C-5
Sum-1
Sum-2
Sum-3
Sum-4
Sum-5
Device-1
Device-2
Device-3
Device-4
Device-5
Device-6
Device-99
11
RT-knobs implementation 3knob functions in the
devices

• Description
• RT output devices send RTknob values to all
  subscribed devices
• The device executes the Knob calculation locally
• The summing of the knob corrections is done
  locally
• Dependencies between knobs values (cross terms)
  can be managed locally on the device.
• RTknobs can be used more easily during ramps.
• Bandwidth usage is the lowest
• Number of knobs knob-update-frequency
• Processing on the device is highest (however, if
  only simple linear knob functions are used this
  should be ok)
• RTKnob values can be broadcast (no point to point
  communication). It could use the slow-timing
  services or any other means.
• The ramp itself could be implemented as an RTknob
  (although in reality one will not have all the
  freedom as one may think, e.g. variable ramp
  speeds, due to dynamic effects).

12
RT-knobs implementation 4knob functions
distributed as processes of local fieldbus masters
RTdev-1
RTdev-2
RTdev-3
Knob D
Knob C
Knob B
Knob A
Function A-6
Function A-99
timing
Gateway controller
Gateway controller
Ranp Function R-1
Ranp Function R-2
Ranp Function R-3
Ranp Function R-101
Ranp Function R-102
Function A-1
Function A-2
Function A-3
Function B-2
Function B-3
Function B-101
Function C-1
Function C-102
Sum-1
Sum-2
Sum-3
Sum-101
Sum-102
Fieldbus
Fieldbus
Device-1
Device-2
Device-3
Device-101
Device-102
Device-6
Device-99
13
RT-knobs implementation 4knob functions
distributed as processes of local fieldbus masters

• A combination of implementation 1 and 3.
• Processing is done distributed in processors that
  have access to the local equipment bus.
• The high bandwidth communication is isolated on
  the local equipment bus.
• This system is more appropriate for local
  feedback loops.
• The function generation could be implemented in
  software modules running on the local processors.
• More flexibility on the long term.
• Simpler electronics.
• Function generation (for test and debugging) can
  be done locally from the local equipment bus
  control processor.