Blomberg, B.R. Back, B. Bunnell, K.J. Clark, J.A. Hendricks, M.R. Peters, C.E. Reyna, J. Savard, G. Stanton, D. Weber, L. JACoW Publishing Geneva, Switzerland 2673-5547 978-3-95450-240-0 10.18429/JACoW-HIAT2022-TUP11 English 96-99 radiation controls operation Linux PLC Contribution to a conference proceedings 2022 2022-08 https://doi.org/10.18429/JACoW-HIAT2022-TUP11 https://jacow.org/hiat2022/papers/tup11.pdf ATLAS (the Argonne Tandem Linac Accelerator Sys-tem) is a superconducting heavy ion accelerator which can accelerate nearly all stable, and some unstable, iso-topes between hydrogen and uranium. Prompt radiation fields from gamma and or neutron are typically below 1 rem/hr at 30 cm, but are permitted up to 300 rem/hr at 30 cm. The original ATLAS Radiation Interlock System (ARIS), hereafter referred to as ARIS 1.0 was installed 30 years ago. While it has been a functional critical safe-ty system, its age has exposed the facility to high risk of temporary shutdown due to failure of obsolete compo-nents. Topics discussed will be architecture, hardware improvements, functional improvements, and operation permitting personnel access to areas with low levels of radiation.