Sunday, April 30, 2017

Chosing a new oscilloscope

Since I will be doing development for our EGSE, I should try to get a good oscilloscope ordered that will meet my needs.

Basically, the choice is between Tektronix and Agilent. I tend to like Tektronix, other people despise them for some reason.

I need to have a 16 channel logic analyzer built in.

For Tektronix, that one criteria narrows down the series of scopes that I am interested in to just two, the MDO3000 series and the MDO4000 series.
The most basic MDO3000 option, the MDO3014 is a 100 MHz scope with a 16 channel logic analyzer with 121 ps resolution. http://www.tek.com/oscilloscope/mdo3000-mixed-domain-oscilloscope
It isn't that much more money to get a MDO3024 which is the same scope at 200 MHz with the same logic analyzer.http://www.tek.com/oscilloscope/mdo3000-mixed-domain-oscilloscope
The MDO4000 has scope resoutions up to 1 GHz which we probably don't need. However the bottom of the line MDO4024C is a 200 MHz scope with a 16 channel analyzer with a much nicer 61ps resolution: http://www.tek.com/oscilloscope/mdo4000c-mixed-domain-oscilloscope
Note that the logic analyzer probe set is model number P6616. Its specs say that it's good only up to 500 KHz and pulse widths of 1 ns, so hopefully the 61 ps resolution of the scope can still be met!http://www.tek.com/manual/p6616

Agilent, now Keysight, has a couple of compatible scopes. It is not immediately clear from their website though what the resoution of their logic analzyers are.
Their MSOX3014T is a 100 MHz scope with a 16 channel logic analyzer: http://www.keysight.com/en/pdx-x202181-pn-MSOX3014T/mixed-signal-oscilloscope-100-mhz-4-analog-plus-16-digital-channels
The is the same scope in 200 MHz. http://www.keysight.com/en/pdx-x202183-pn-MSOX3024T/mixed-signal-oscilloscope-200-mhz-4-analog-plus-16-digital-channels



National Instruments PXI Thermocouple Monitor

Links to educate myself on how to set up temperature monitoring for my PXIe chassis computer from NI.

The hardware being bought by the other team is a PXIe-4353 module and associate TB-4353 terminal block:
http://www.ni.com/en-us/shop/select/pxi-temperature-input-module?modelId=123621
http://sine.ni.com/nips/cds/view/p/lang/en/nid/208292

NI has a few nice introductory articles on their temperature monitoring products that I should read:
How to use thermocouples, thermistors, and other devices: http://www.ni.com/temperature/
Choosing a Thermocouple Measurement Devicehttp://www.ni.com/white-paper/7108/en/



Monday, April 3, 2017

M$ Excel 2013 EVAL function

I wanted something in Excel to take a cell that had a string that was a formula and produce the results of this formula. There used to be an "EVAL" function, or maybe I'm just remembering something from another language, but anyhow it isn't part of my Excel 2013.

Amazingly, there is a workaround! The trick is to make a function, that has the cell with the formula in it as an argument, using "Define Name" hidden under "Name Manager". The nice thing about this is that it obeys the rules of expanding down rows, such that if you define a named function for one cell that uses another cell (presumably but not necessarily in the same row), then you just pull the corner of that cell down and the functions placed into the new cells use the corresponding cells in the same downward direction.

Here is the nicest tutorial online at the moment for how to do this: http://www.myonlinetraininghub.com/excel-factor-12-secret-evaluate-function