The machine tool coordinate system shifts before and after RTCP is turned on

Hello everyone, I'm a DIY enthusiast. My English isn't great, but I'll try my best to explain clearly. I'm encountering a problem while using LinuxCNC as the operating system for my machine tool. When I replace the existing kinematics system with my own custom-built five-axis kinematics system, the machine tool coordinate values ​​change when I switch to RTCP mode at the current position, causing a system alarm because the machine tool coordinate system has exceeded its limits. My understanding is that enabling RTCP changes the workpiece coordinate system values, not the machine tool coordinate system values. I haven't been able to solve this problem yet.

Additionally, my machine tool structure is A (head), C (table), with the distance from the C rotation center to the machine tool zero point being (Xrc, Yrc, Zrc). The tool length is set to dt, and there is an offset between the two rotary axes with offset values ​​of (Xos, Yos, Zos).

Thank you for your reply. Currently, my kinematics has coordinate offsets of (Xrc+Xos, Yrc+Yos, Zrc+Zos) when A=0, C=0. As you mentioned, "the coordinate values ​​remain consistent when switching between simple kinematics and RTCP kinematics." Therefore, it's certain that my kinematics might have a problem. I also have a few questions:

1. Is it necessary to use the tool tip coordinate system as the basis for deriving the kinematics?

2. I noticed an article on kinematics derivation, which I've attached. After deriving my machine tool kinematics using it as a standard, can I directly replace the XYZAC kinematics code in my code? Or do I need to do something else?

I will immediately put these two questions into practice.

Looking forward to your reply.