  Commercially available computer-controlled SQUID electronics are usually
delivered with software providing a basic user interface for adjustment of
SQUID tuning parameters, such as bias current, flux offset, and feedback loop
settings. However, in a research context it would often be useful to be able to
modify this code and/or to have full control over all these parameters from
researcher-written software. In the case of the STAR Cryoelectronics PCI/PFL
family of SQUID control electronics, the supplied software contains modules for
automatic tuning and noise characterization, but does not provide an interface
for user code. On the other hand, the Magnicon SQUIDViewer software package
includes a public application programming interface (API), but lacks
auto-tuning and noise characterization features. To overcome these and other
limitations, we are developing an "open-source" framework for controlling SQUID
electronics which should provide maximal interoperability with user software, a
unified user interface for electronics from different manufacturers, and a
flexible platform for the rapid development of customized SQUID auto-tuning and
other advanced features. We have completed a first implementation for the STAR
Cryoelectronics hardware and have made the source code for this ongoing project
available to the research community on SourceForge
(http://opensquid.sourceforge.net) under the GNU public license.
