Homogenizing a control system with a long history

The LANSCE Accelerator is over 50 years old, the original control system was fully replaced with an EPICS control system a few years ago. However, the upgrade process was slow, and the "new" control system has processor boards that are 30 years old, as well as new soft-core FPGA processors. We have eliminated VXI and almost eliminated CAMAC crates, but also have VME, VME64, cPCI, and VPX. The control system uses 4 types of VME processor boards and 3 real-time operating systems. The diversity in the control system makes it difficult for new personnel to support everything, as well as making maintenance more difficult. We are in the process of consolidating to fewer hardware platforms and rewriting software that has incurred too much technical debt, while also developing new replacement technologies for upgrade projects. Most of our hardware I/O has been converted to compact RIO based systems. Our timing system cards are either VME or cPCI. VME has had a very long support life, VPX also looks promising for a long support lifetime. We are currently planning to develop a solution with an IP-based event receiver so that it will be easier to migrate to new commercial off-the shelf FPGA boards. We are also hoping to move away from VxWorks. Newer device support is being converted to operating system independent software using asynPortDriver. Simplifying the hardware and software is the key to sustainable maintenance.