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Overview

I need to create an analog voltage of 0V-10V for the PLC with a microcontroller with operating voltage 5V.

Approach

I've been doing this research since last week. I'll share the results of my research. I need your feedbacks.

First of all, my microconotroller dont have any DAC module. So I'm going to produce an analog signal through the I2C with the mcp4725. (https://www.sparkfun.com/products/12918)

I will then raise this signal to 10V with an opamp.I think I will use this LMV358 module. (https://www.sparkfun.com/products/9816)

There's a problem here. I need a lot of these analog outputs. But the mcp4725 addresses are restricted. So I will multiply I2C addresses with TCA3548A. (https://www.adafruit.com/product/2717)

The modules I use are ready products. I think I don't need to draw a schematic. Anybody have a better idea? Do you think this works? If it works, will it make any problems?

Yes, I need your comments and suggestions.

Best regards

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    \$\begingroup\$ You'll need a 12 volt supply for the op-amp - op-amps don't just magic-up voltages without the proper power rails. You might also consider using a small negative rail too. \$\endgroup\$ – Andy aka Mar 7 at 11:16
  • \$\begingroup\$ It should work, however.. it seems a bit umm.. "inelegant".. to convert many channels of digital to analog and then back to digital. Can't you talk serial digital to the PLC? \$\endgroup\$ – Spehro Pefhany Mar 7 at 15:21
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There is a simpler way to do that with PWM + Filter, you don't need a DAC and is much easier to translate to 10V and is cheaper.

The opamp is a buffer stage that is optional and depends if your PLC has a high impedance or not. You need a rail to rail opamp (might need a different part that there is on the schematic).

PWM signal is directly 0-3V or 0-5V and the output is 0-10V. The output might not be directly linear, but this you can adjust in the code.

This circuit will have a small ripple, you can add more R-C filter stages or increase C1 to reduce it.

schematic

simulate this circuit – Schematic created using CircuitLab

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