I have tried to design a circuit for controlling the CAN bus 120 Ohms termination resistance by using a 3.3V GPIO from a STM32 MCU.
In the SSR datasheet, it specifies that the LED voltage should typically be 1.27V. So by using a voltage divider with 3.3V input and R1 = 20k, R2 = 13k that would result in 1.3V. I understand the issues regarding timing of the bus resistance etc. but since the customer of the product should open the box with the PCB, using physical switch is not preferrable.
The ON-state resistance is specified as 0.3 Ohms max, so the bus resistance should not be an issue in my opinion. I have not used SSR like this before, so if anyone could verify if the design should work in theory, that would be very helpful.