Transient Voltage Suppression

4 05 2010

When the fusor’s plasma becomes unstable and sparks, it makes my DAQ crash. This is likely due to transient voltage spikes in the wires, or electromagnetic interference through the air.

I’ve been exchanging emails with Raymond R. about the details of voltage suppression. He suggest using TVS diodes to protect each channel of the DAQ from voltage spikes in the wire by clamping them just above  the channel’s operating range.

I’ve ordered these TVS diodes:

1.5KE7.5CA

1.5KE12CA

Raymond suggests the following:

1) Buy the  NI USB-6000 Series Prototyping Accessory if you have the money and want to avoid messiness; otherwise you can kludge the wiring. (I’ve done this).

2) 16 (+ 4,5 spares) of  LCE10A-ND (I bought corresponding parts at mouser).

3) Go to differential mode on NI USB 6008 (good idea).

4) Connect the TVSs from each input/output line to  frame ground.

5) Take the cable shield and do not connect it at the USB board; connect back to the computer frame.  The TVS diodes go to the cable shield not to the USB box grounds.  Connect the USB grounds together and to the shield ground through a 1 meg resistor (alternately a .1 uf ceramic cap).





Mass Flow Controller Online

21 10 2009

Big day. Big win. Big upgrade.

Got the mass flow controller online!

IMG_4322

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Computer Controlled Sorensen Hack

7 10 2009

Sweet! Just got the high current (120 Amp) Sorensen power supply working with computer control (to power the superconducting magnet).

Here is a video:

Details after the jump.

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Reactor Controller / Data Acquisition

17 09 2009

Since the pump broke I’ve been working on the reactor controller / data acquisition system. This will allow us to record:

Voltage reading (via voltage dividers and ammeter shunts); low power voltage reading from magnetometer, thermocouple, pressure gauge, etc; on the output side: voltage control of power supplies, servos for needle valves, triggering IGBTs; Our ion gauge has the option of digital over RS485.

I purchased an NI USB-6008 (manual, driver):

IMG_4042

Unfortunately the driver for this does not work with Snow Leopard yet. I’ve already upgraded my main laptop to Snow Leopard and I really don’t want to downgrade to Leopard so I dug up and old G4 running Tiger. Had to swap out a broken CD drive:

IMG_4038

This G4 will be a challenge to upgrade to Leopard as it lacks a DVD drive, although it may be possible to install without DVD.

I was able to install the driver NI-DAQmx_Base. I opened up NIdatalogger and performed a successful grab of voltage data on the analog input:

NIdatalogger

I would like to get this ruby adapter working. So far I can’t get it to build on Tiger (it makes it further on Snow Leopard). I’m working with the creator to get it installed and working:

make -f Makefile.swig install
swig -ruby -Fstandard -I/Applications/National\ Instruments/NI-DAQmx\ Base/includes -o daqmxbase_wrap.c daqmxbase.i
make: swig: Command not found
make: *** [daqmxbase_wrap.c] Error 127
make -f Makefile.swig install
swig -ruby -Fstandard -I/Applications/National\ Instruments/NI-DAQmx\ Base/includes -o daqmxbase_wrap.c daqmxbase.i
make: swig: Command not found
make: *** [daqmxbase_wrap.c] Error 127
—————-
UPDATE:
I just needed to install SWIG. Although this took roughly 6 hours! It installed without a problem.
I AM UP AND RUNNING with data acquisition in my native programming language ruby.




Superconducting Cable

21 12 2008

On Dec 4th 2008, I ordered 20 meters of 4mm YBCO superconducting cable from theva. The lead time is 8 weeks, so it hopefully will arrive at the end of January 2009. This should be more than enough cable to complete several basic tests of superconductor construction. I also want to explore the fabrication of a SMES device for high power, high speed lab power supply. We will need to devise circuits to charge and discharge the superconducting cable, I’m not seeing much information on this topic on the internets.  And of course this will require liquid nitrogen. I’ve always wanted to play with liquid nitrogen.





NYC RESISTER

13 11 2008

Last night I attended NYC Resister for the first time… wow. Really impressive. Talented, well equipped, and fun. In 5 hours I went form zero knowledge to a working computer controlled stepper motor using the reprap electrical hardware. I can’t understate how much more productive and fun it is working with like minded individuals.