Hello, I was wondering if someone could please help me find a digital potentiometer to replace a mechanical one with that way I can control it using an arduino.
A digital pot may not be appropriate in several aspects. The first is the voltage applied, the most common parts cannot tolerate more than 5 volts applied to the high end or supply side of the pot. 24vdc is the Phoenix module supply voltage, it's probably not what is actually apply to the pot. Fortunately, it is a simple matter to measure the voltage supplied by the module. If more than 5 volts is applied to the pot, have a look at the MicroChip MCP41HVX1 parts, they can handle up to 36 volts if you meet the wiper current requirements.Another issue is the resolution. Digital pots typically have a maximum resolution of 8 bits or 256 distinct steps, some are only 7 bits. Your application may or may not need more resolution than is available and practically speaking, a motorized analog pot (with your cermet element) is considered to have an almost infinite resolution. In reality it cannot be infinite but it's certainly better than 7 or 8 bits. Realistically, anything beyond about 13 bits isn't going to help since the limimiting factor is the output resolution of the MCR-2-POT-UI. Resolution is the bigger factor of the two and it's the more difficult to quantify especially since we don't know the final application.