@felmue RP has the pull-ups by default. Although these are brand new wires, I've tried different ones. I've also tried it with and without the power to the stack. I've also tried speeds of 50k, 100k, and 400k, which have all worked for other i2c devices on the Pi.

@robski I do not. I was considering getting a core and base to make sure it worked with those first to rule out the device.

@robski Yes, the single channel unit was behaving the exact same way.

@robski

I was hoping there wasn't something unique about the I2C on these, so I'm glad you confirmed that, however it's still confusing why I can't even detect it. Here it is with the stack module hooked up https://docs.m5stack.com/en/module/AIN4-20mA%20Module%2013.2. When I have SDA and SCL disconnected, an i2cdetect immediately returns no results. When I hook them up, i2cdetect crawls through each address until they time out. I've double checked the pinouts, and made sure I'm supplying 12v (also tried 24v) to the 9-24V high voltage plug, and that it's getting 5v from the Pi.

Yellow - 5v
Brown - Ground
Orange - SDA
Red - SCL

@holofloh Thanks for the reply. I'm using a raspberry pi 4 with 5v that draws directly from it's own power supply https://pinout.xyz/pinout/i2c. I tried hooking up to an external 5v power supply and it still doesn't detect either the unit or the module.

I am trying connect the AIN4-20 current sensor to the raspberry pi and communicate directly with i2c. i2cdetect fails to find the device (I've tried both the single channel unit and the 4 channel stack). I've enabled and tried the built in ARM i2c (bus 1), and also the software i2c (bus 3). Other i2c devices show up on these busses, just not the m5 products. Should these be detected, or are they not compatible without a M5 host? I have a raspberry pi project that uses another company's industrial i2c current receivers, but they are 12-bit units, and was hoping to easily upgrade to m5 units.