Why are we here and what are we
trying to accomplish?


The existing system of cross connects based on
terminal blocks and discrete wiring has served it’s
purpose, but has become unwieldy, particularly in
light of the EMI retrofit.
In many cases, we have blindly(?) applied our new
EMI policies and the result has been to place as
many as 6 EMI filters in our slow control and
monitoring signal paths. This is certainly overkill and
probably detrimental.
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What do we like about the cross
connects?




Flexibility- During installation and commissioning
activities you can easily reconfigure to support
changing needs.
Simplicity- There are no active components. It is
tough to beat a wire for simplicity.
Verification- It is relatively easy to get to signals
during debug.
Commercially available- The pieces used to put the
system together are all readily available from multiple
vendors
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What don’t we like?





Configuration Control- While wires are simple, lots of
wires can become a rat’s nest. The documentation
must be kept up to date.
Operational Problems- Wires can come loose during
debug and operations and can be hard to find.
Size- They take up a lot of space.
Cross talk and interference- The large loop area of
many of the signal paths are susceptible to
interference.
Cost- The current EPICS interface via VME can have
a high per channel cost.
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How do we keep what we like and get
rid of what we don’t?

Focus on the real problems»
»
»
»
»

Size
Unwieldiness
Overkill in EMI upgrade
Intermittency
…….
Focus on the good things
» Commercially available
» Flexible
» Simplicity
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Block Diagram of One Possible
Solution
Analog Module
or Chassis
Cross
Connect
Board
Analog Module
or Chassis
Cross
Connect
Board
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DAC
CPU
Channel Access
DIO
EPICS IOC CHASSIS
Analog Module
or Chassis
Analog Module
or Chassis
ADC
ADC
DAC
CPU
Channel Access
DIO
EPICS IOC CHASSIS
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Features




Analog modules or chassis are connected to EPICS
IOC Chassis via shielded cable, EMI feedthroughs,
etc.
Cross connect board is used to connect from
modules to control ADCs, DACs, DIO, ala the current
cross connects.
Commercial ADCs, DACs, DIO and CPUs would be
used
CPU runs EPICS and connects to existing control
network via fiber Ethernet.
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What type of CPUs, bus, modules, etc
could be used?

There are many alternatives available
»
»
»
»
PC104
PCI
USB
….
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What has already been done within the
collaboration?

EPICS has been ported to Linux based embedded
CPUs and PCs
» PC104
» PCI
» As far as we know, USB devices have not been done, but
development does not appear to hard.
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What would one of these solutions look
like and cost?


As a design example and exercise, the 40M LSC
auxiliary controls cross connects was replaced with a
PC104 based system. The 40M LSC is very similar to
the site LSC systems.
The ADC, DAC and DIO functions are done using
Aquarela Systems model AQ30-12212-104 and
AQ20-2424-104A modules.
» There is nothing special about these modules. They were only
chosen as an example. Final choices would be the result of a more
detailed study

A CPU was not chosen, but there are many available.
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ADC, DAC and DIO for Design
Example
AQ30-12212-104 Analog I/O Module with General Purpose I/O and PWM
Analog Input:
14 channel 12 or 16-bit resolution
0 to 5V / 0 to 10V / -5 to 5V / to 10V individually selectable ranges
100 Ksps conversion rate
Internal sample buffer for high speed acquisition
Analog Output
8 or 16 channel 8 or 12-bit resolution
3 us settling time
5V output range
General Purpose I/O and PWM
2 general purpose TTL I/O that can be configured as input, output or PWM output
4 general purpose TTL I/O that can be configured as input output or 10-bit to 5V 20 us analog input
AQ20-2424-104A Digital Output
24 Line Buffered Output (3 X 8-bit Ports)
7 to 35V DC Operation
100 to 350mA Depending on Duty Cycle
Thermal Overload Shut Down
Over-Current Protection
LED for Fault Indication
Software Fault Indication
Software Fault Reset
Internal Ground Clamp Diodes
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40M LSC Example



Due to the modularity of the system it would require only one
type of IOC chassis. Each with the same cross connect board
and similar EPICS software.
The system require 4 of these chassis. Three of the chassis
would be more fully utilized, but still have extra channels and
one chassis would be lightly utilized.
Each chassis would have:
»
»
»
»

One CPU
Two AQ30-12212-104 Analog IO modules
One AQ20-2424-104A Digital IO module
One fiber to e-net converter
Each chassis would take up 2U of rack space
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40M Example cont’d



There is also a requirement for one cross connect
chassis to assemble get signals to/from the front end
XY220s.
This chassis contains only a cross connect board.
Schematics for the example are located on Jay’s web
page.
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40M Example Costs

IOC Chassis:
»
»
»
»
»
»
»


CPU- ~$400
Analog IO- 2x$265.85
Digital IO- $99
Cross connect board- ~$100
E-net to fiber-$100
Chassis, cables, emi feedthroughs, misc- ~$1000
Total chassis cost- $2231 ea. X 4 chassis= $8924
XY220 Chassis- ~$600
Total cost minus cables- ~$9500
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40M Example Costs cont’d

What does it replace?
» Two auxiliary VME crates, CPUs, ADCs, DACs, BIO….
» All cross connect blocks, wires
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40 Meter LSC Design Example
Alternatives

Alternatives to the Aquarela System boards:
» Diamond Systems Diamond-MM-32-AT
» Diamond Systems Ruby-MM-1612
» Many others

The PC104 based solution used in the design example could be
replaced with a USB based solution.
» The CPU would be a Linux based embedded CPU running EPICS.
» IO would be accessed via a local USB inside the chassis.
» Example of the USB IO devices that could be used are available from:
– FiberByte DAQ-16-4-32, DAQ-16-0-16, DAQ-0-16-16
– Measurement Computing Personal Measurement Device Series
– Others

We could also use an embedded CPU with PCI slots. This
solution would be very similar to the EPICS systems we have
already developed for the TCS and TNI.
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Conclusions




There are a wide variety of solutions available.
Many solutions involve little custom hardware design
beyond our requirements for custom interconnects
Many solutions would involve modest amounts of
software porting and development, but much of it
may already be available.
A more detailed study and analysis of our
requirements and available technologies could lead
to a solution that would meet most if not all of our
current and future goals.
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