Input voltages and modbus temp connection

[nanok66]

Hi, I have an existing project that I am thinking of migrating from a Pi Compute to the RevPi's.

I'm thinking of buying the RevPi DIO. I have a bunch of inputs that work with 24V but I have one optical sensor that uses 5-12V. Is there a recommended method to interface this voltage mismatch? Or are the RevPi inputs open collector/drain?

I'm looking to connect a single temperature sensor to the RevPi. I will have one of the core RevPis, one RevPi DIO, and one RevPi DO. Do I need an additional unit if I am looking to connect just one temp sensor? It looks like one temp sensor can be connected via USB.

Also I am trying to source this modbus adapter but I am not sure where to find an inexpensive adapter. The temp sensor I will use will have to fit in a thermowell hole that is around 3/8". I cannot use some combo temp humidity sensor that I am commonly seeing. If possible I prefer a sensor that is not already encased in metal, just the raw sensor like I would buy from digikey. Any suggestions?

[crismancich]

>> I'm thinking of buying the RevPi DIO. I have a bunch of inputs that work with 24V but I have one optical sensor that uses 5-12V. Is there a recommended method to interface this voltage mismatch? Or are the RevPi inputs open collector/drain?

Seems like your sensor is an analog sensor, right? Then the AIO or MIO module would be the way to go.
https://revolution.kunbus.de/shop/de/di ... -revpi-mio

>> I'm looking to connect a single temperature sensor to the RevPi. I will have one of the core RevPis, one RevPi DIO, and one RevPi DO. Do I need an additional unit if I am looking to connect just one temp sensor? It looks like one temp sensor can be connected via USB.

Of course you can use USB sensors. Please make sure there's arm drivers for the sensor.
The common way of using temp sensors is the AIO module with PT100 PT1000 sensors. But with a trick you can also use MIO, FLAT, Compact analog IOs if you add a capacitor and do the calculations yourself. (With a known resistor R ohms law allows you to calculate the current when measuring the voltage.)

>> Also I am trying to source this modbus adapter but I am not sure where to find an inexpensive adapter.
All RevPis have on-board Modbus TCP. Do you refer to RTU?

>> The temp sensor I will use will have to fit in a thermowell hole that is around 3/8". I cannot use some combo temp humidity sensor that I am commonly seeing. If possible I prefer a sensor that is not already encased in metal, just the raw sensor like I would buy from digikey. Any suggestions?

Please note that you will not have direct access to the GPIOs in the same way as you have it on Raspberry Pi.
RevPi is made to be used with standard industrial DIGITAL AND ANALOG sensors. Commonly PT100 / PT1000, 5-10V, 4-20ma as mentioned above.
RevPi is made