Deibele, C. Mahoney, K.L. Williams, D.C. JACoW Publishing Geneva, Switzerland 2226-0358 978-3-95450-209-7 10.18429/JACoW-ICALEPCS2019-WEPHA092 English 1304-1306 WEPHA092 PLC timing controls target operation Contribution to a conference proceedings 2020 2020-08 https://doi.org/10.18429/JACoW-ICALEPCS2019-WEPHA092 https://jacow.org/icalepcs2019/papers/wepha092.pdf The Controls Group at the Spallation Neutron Source (SNS) is designing a programmable signal processor based credited safety control that calculates pulsed beam energy based on beam kinetic energy and charge. The SNS Pulsed Energy Limit System (SPELS) must reliably shut off the beam if the average power exceeds 2.145 MW averaged over 60 seconds. This paper will cover the architecture and design choices needed to develop the system under the auspices of a programmable radiation-safety credit control. The authors will also introduce the concept of a graded failure approach that allows the credited system to continue operation in the presence of some faults.