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House battery project is almost done but the required terminating resistor is AWOL. I only have a couple 100s and lots of 470s. I could get close by paralleling 2 100s and put another 100 in series --> 150 Ohms. Or parallel four 470s --> 118 Ohms.

I don't know about the tolerances for Modbus termination. Anyone know if a single 100 Ohm resistor has a chance of working?

Edit: Cable length is about 29 ft (~9 meters) Cat6

House battery project is almost done but the required terminating resistor is AWOL. I only have a couple 100s and lots of 470s. I could get close by paralleling 2 100s and put another 100 in series --> 150 Ohms. Or parallel four 470s --> 118 Ohms. I don't know about the tolerances for Modbus termination. Anyone know if a single 100 Ohm resistor has a chance of working? Edit: Cable length is about 29 ft (~9 meters) Cat6

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[–] • 1 pt

It's an RS485 interface, so I guess 4-20 mA?

[–] • 1 pt

Beyond that I'm useless. Basically for DC PIDs you just do V = I*R so using a higher resistance means you'll register higher voltages. Which may not translate to correct readings for your system.