Dale has a good post up on Achilles which was Eric's project with help from an oil company before he founded Byres Security.
I would describe Achilles as a fuzzer for SCADA and DCS systems.
There was an effort (well thought really) to build Achilles testing into SP99 that Jay White at Chevron, and a couple of other oil industry guys were thinking of chasing shortly after the first SANS scada conference. I am not sure where it went. If I remember right Michael at INL and Ray and Sandia were also in that conversation briefly.
A standardized way to approach the process would be good for all ACS using industries.
This post at Computerdefense covers quite a few fuzzers not related specifically to SCADA.
More Fuzzing Detail here.
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