I have a 8-channel verified and system-tested design, it is absolutely bulletproof. If you are interested, contact me. Rather than designing pcb , question how reliable the system is and its certification.There is reverse voltage protection at the input. I can quickly offer more than one circuit that provides protection to the input, again from verified circuits.At the same time, if you need a chassis, I can send it to you as well.Products that are not examined for hours under a thermal camera are generally garbage.There is a tolerance of +-20 microamperes when PCB production is provided under the necessary conditions.The leakage current is at 1u ampere level.