Design of control instrumentation of two in-vacuum undulators IVU25S

This paper summarizes the primary controller that is based on Siemens S7 PLC for two in-vacuum undulators to be installed at SSRF. The PLC controls a single gap stepper motor with a separate motor for taper control. Position feedback is derived from two SSI linear absolute encoders mounted across the gap at either end of the array to measure taper. All vacuum pump controls are provided along with cooling water control and a separate bake-out controller. This system is designed for Shanghai Synchrotron Radiation Facility, SSRF, a third-generation synchrotron radiation light source, with the total power is 600 KW, energy 3.5 GeV, circumference of 432 meter, and current of up to 300 mA.