I am working on a project with 3 PCB : PCB1 is the master, it communicates with two slaves, PCB2 and PCB3.
PCB1 is powered by a battery and it redirects the supply to PCB2 and PCB3. Each PCB includes a microcontroller and an RS-485 transceiver.
There is a cable from PCB1 to PCB2 and another from PCB1 to PCB3. Both cables are the same. There length is approximately 50 cm. They include 6 wires : 4 wires for the RS-485 (the communication is full duplex), and 2 wires for the supply.
It looks as follows : I need to add an ECG sensor on PCB1. It simply measures the potential difference between two analog inputs. The first input needs to be connected to one pad on PCB2, and the other to another pad on PCB3. I was thiking of adding 1 wire in each cable to make the connection. It would look as follows : But there would be analog and digital signals in the same cable. Is this a problem ? If so, what are the solution to transmit digital and analog signals at the same time ?