Sato, K.C. Kamikubota, N. Kimura, T. Yamada, S. Yamamoto, N. Yoshida, S.Y. JACoW Publishing Geneva, Switzerland 2226-0358 978-3-95450-209-7 10.18429/JACoW-ICALEPCS2019-WEPHA136 English 1418-1420 WEPHA136 EPICS operation controls GUI status Contribution to a conference proceedings 2020 2020-08 https://doi.org/10.18429/JACoW-ICALEPCS2019-WEPHA136 https://jacow.org/icalepcs2019/papers/wepha136.pdf In J-PARC, a Machine Protection System (MPS) stops accelerator beam operation automatically when an interlock signal comes. Normal MPS accepts interlock signals by hard-wire, but a software-based MPS, called "Soft-MPS", uses only EPICS PVs without wiring. A PLC controller running Linux was introduced to watch at some EPICS PVs over Ethernet, and outputs Soft-MPS signals to the MPS unit after logical calculates. There are 2 reasons of using Soft-MPS. (1) To install interlock signals rapidly. This type of Soft-MPS will switch to hard-wire later. (2) To use non-hardware parameters: for example, machine operation modes, beam bunch information, etc. From the first Soft-MPS setup in 2018 spring, 9 Soft-MPS signals are currently used. As more Soft-MPS signals are expected in the future, we need to discuss the policy.