Use of the TACL system at CEBAF for control of the cryogenic test facility

A description is given of a logic-based control software system called Thaumaturgic Automated Control Logic (TACL), which is under development at the Continuous Electron Beam Accelerator Facility. The first version of the software was placed in service in November 1987 for control of cryogenics during the first superconducting RF cavity tests at CEBAF. In August 1988 the control system was installed at the cryogenic test facility (CTF) at CEBAF. CTF generated liquid helium in September 1988 and is now in full operation for the current round of cavity tests. TACL is providing a powerful and flexible control environment for the operation of CTF. A description of the TACL control system covers the logic editor, the display editor, run-time processes, the graph-plotting program, the PID (proportional-integral-deviation) control algorithm, and fault protection.<
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