I'm using a homebrew encoder based on two A3144 hall sensors (logic, open collector) to control motor rotation. It's connected to the MCU via 2 metres of fancy double-shielded cable with 1K pull-up resistors and tends to work pretty well.
But now I need to connect to that same encoder from 20..30 m away from the MCU. Environment is quite noisy, so I want to use RS-485 ICs and twisted pairs for that task. The RS-485 will just carry encoder pulses, not some data.
The only downside of this solution that I can think of is power dissipation. Depending on the rotor position, an RS-485 line can stay high for minutes, running current through the termination resistor.
I think that RC termination should do the trick, but I'm not sure how to calculate the capacitor value. The pulse frequency is 75..300 Hz, so extremely low compared to normal RS-485 operation. Maybe there is some solution suitable for my case that is not recommended for RS-485 networks.
I know that there are some industrial encoder protocols based on RS-485, but they look over-complicated for this task.