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Yes, we test IGBTs

Posted by Peter Hiscocks on 10/6/2016 to Software
We were asked the other day whether our curve tracer CTR-101 can test IGBT devices.

What's an Insulated Gate Bipolar Tranistor (IGBT)? If you live in a world of small analog signals (that's us), then you probably haven't used an IGBT. But if you work in high power applications such as variable speed drives for induction motors or welding controllers, you've probably used them.

The IGBT is one of those hybrid devices that is 'the best of both worlds'. It combines the high input impedance of the MOSFET with the low saturation voltage of the bipolar transistor.  The IGBT is used almost exclusively as a switching device, so in the ON state, the power dissipation is proportional to the saturation voltage.  Smaller saturation voltage results in less power dissipation and simplified cooling requirements.

We ordered some of the IGBT model IRG4PF50 to test on the curve tracer. The specifications are impressive: 900 volt breakdown voltage, 51 amps current, 200 watts, all for $6 from Digikey.  Even allowing for the limitations of heatsinks and thermal resistance (which always make the actual power less than shown on the spec sheet), this is an impressive device.

The CTR-101 can measure up to 30 volts or so at a test current of 1 ampere: it's intended for small signal devices.  But we can test the behaviour in the small signal region.  This would be useful, for example, if you needed to match one or more units.

The figure shows the results: on the N-MOSFET setting of the curve tracer, we get a family of curves similar to an enhancement mode MOSFET.  There is certainly enough information here to determine the gate threshold voltage and match device characteristics.  So yes, the CTR-101 can measure the characteristics of an IGBT.

A transfer characteristic (drain current vs gate-source voltage) might also  e useful: if you have some interest in that, give us a shout and we'll add that feature to the software.

Peter Hiscocks
October 2016


Waveform Averaging

Posted by Peter Hiscocks on 3/23/2016 to Software

Click here to read our latest application note on waveform averaging in the CircuitGear software.  Waveform averaging can be very useful in extracting a signal from noise as long as a solid trigger signal is available.  The application note shows how a software contribution from a Syscomp customer can significantly improve the signal-to-noise ratio using waveform averaging.

Syscomp Software on the Raspberry Pi 2

Posted by Peter Hiscocks on 8/20/2015 to Software
Recently, we have been evaluating the Raspberry Pi 2 computer. For those who have been visiting a distant part of the galaxy for the last few months, the Raspberry Pi 2 (RP-2) is a single-board computer, about the size of a business card, that runs Raspian, a Linux variant that is very similar to Debian linux. 

For example, one can download and install software using an internet connection with the standard command 'sudo apt-get install name-of-package'. The boot sequence looks very similar to the sequence we used to see, years ago, on a very expensive Sun Workstation.


I'm *very* impressed by this device. The network connection and video worked immediately.  In a few minutes, I was able to configure a new password, change the keyboard configuration to Dvorak, and install a bunch of useful programs - such as the Joe editor.

There's been some interest in running Syscomp software on this platform, so we investigated that possibility.

Syscomp software is written in the Tcl language, and happily Tcl/Tk 8.5.11 is included in Raspian.  So the majority of the code runs correctly.  We use some 'packages' that are written in Tcl/Tk, and so they should (and do) run correctly.  We also use some packages that were written in C and compiled for a specific architecture.  In the past, we have taken care of that by bundling them with a platform-specific executable.  But the compiled packages won't run on the Pi unless they are re-compiled.

It turns out that those compiled, platform-specific packages can be replaced in various ways.  For example, we converted all the .png formatted images to the .gif version, using the Imagemagick 'convert' command.  That eliminated the requirement for the Img package.  The Tktable package is used in the curve tracer software: that was replaced by the standard Tcl text widget.  The directories 'Bwidget18Lin' and 'MathLin' (both of which are written in Tcl) were obtained from the DSO-101 software and moved into the software directory.

When these changes are made, code can be run on *any* platform that has Tcl/Tk available, using the command 'wish main.tcl'. That includes the Raspberry Pi.

Here's a screenshot of the Curve Tracer software running on the Pi.


We've also verified that these modifications allow the CircuitGear CGR-201 and Waveform Generator WGM-201 to run on the Pi.

The next release of the software for our various instruments will be modified to eliminate the requirement for platform-specific, compiled packages - so it should run from the wish command on the Linux, Windows, Mac *and* Raspberry Pi 2 platforms.

If you want to port our software to the RP-2 and can't wait for the next release of the software, get in touch and we'll send you a zipfile of the RP-2 version.

Incidentally, the RP-2 is powerful enough to run the CGR-101 software, which is *very* demanding.  Earlier versions of the Pi are too slow to be useable for the CircuitGear software, but they may be capable of running software for less demanding instruments such as the Curve Tracer and Multimeter.

No More Sourceforge

Posted by Syscomp Team on 7/29/2015 to Software
In the past, we have occasionally posted our source code to the SourceForge repository. We've decided to stop using SourceForge, for the reasons shown in this story on Slashdot:


In essence, SourceForge were modifying hosted code to add advertising to the code. This has caught the attention of the open source community: there are currently hundreds of comments on this story. The source code for our products is always available on our website, and that's the official source. We discourage using source code from other sites. Yes, you can read the code to ensure it's not virused or loaded with advertizing, but that's tedious and it's not necessary if you get it from the Syscomp website.

Wavemaker: A Quick Start Guide

Posted by James Gaston on 9/16/2013 to Software

The Wavemaker software tool by John Foster allows one to convert the image of some waveform into the arbitrary waveform file format for a Syscomp signal generator. A new application note providing a quick start guide to using wavemaker has been added to the Resources page.

Running Multiple Syscomp Instruments Simultaneously

Posted by James Gaston on 4/28/2012 to Software
Did you know you can run several Syscomp instruments, simultaneously, on the same computer? Each one gets its own user space and its own serial port. Our software, or your own custom software, can talk to each instrument individually. The photo below is a screen shot of three instances of the CGR-101 operating at the same time. You could also 'mix and match' with different instruments operating at the same time.

Three CGR

Mac OSX GateKeeper Install Issues

Posted by James Gaston on 4/28/2012 to Software
OSX Mountain Lion

Apple have added a new GateKeeper function to OSX Mountain Lion. GateKeeper prevents downoads of our software, so you'll need to disable it while doing the download and install. We're currently investigating to see if there is an alternative solution to disabling GateKeeper.

CircuitGear CGR-101 Software Release

Posted by James Gaston on 4/16/2012 to Software
A new version of the CircuitGear CGR-101 software has been released. Version 19 of the software provides serval bug fixes, improves the automated RMS measurements, adds PNG screen capture, and greatly enhances the functionality of the network analyzer. Visit the download page to get the software.

New CGR-101 Software Release

Posted by James Gaston on 10/18/2011 to Software
A new version of the CircuitGear software has been released. Version 1.18 features several bug fixes, a couple new features, and a brand new usb-serial connection scheme. Visit the downloads section to get the software.

Windows 7 Driver Workaround

Posted by James Gaston on 9/3/2011 to Software
A new application note has been added which contains troubleshooting and installation information for Windows 7 machines. We have discovered that some device drivers can interfere with Syscomp instruments in Windows 7. This short application note provides troubleshooting and work-around information.

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