I just haven't figured out why this needs both 5V and 24V when the sensor will work with either of the voltages.

Me neither, the M340 has input modules that are negative or positive logic capable, if I were implementing a system such as this, I would spec in the most suitable instead of making it hard with external logic.
If you already have the card you intend to use and the logic is opposite, or not swapable, then you may have to place a bipolar transistor to invert it, but the 5v should not be necessary?
Max.

 

I just haven't figured out why this needs both 5V and 24V when the sensor will work with either of the voltages.

Because I want a variable signal. So for example maybe you use the 5v to switch 3v or 5v to switch 12v etc etc. It could work without the multiple voltage sources I'm just trying to have some fun and learn from the idea.

 

Here's a way.

 

Thanks #12 that is very similar to what my professor drew out for me today in school when I showed him what I was having trouble with

 

Thanks #12 that is very similar to what my professor drew out for me today in school when I showed him what I was having trouble with

What course is this?
Before you connect that up you would need to know the sink current required by the input card.
As a general rule, shunt input is not recommended or normal practice, although it may work in this instance.
Also recognize you have an inversion on the input.
Max.

 

What course is this?
Before you connect that up you would need to know the sink current required by the input card.
As a general rule, shunt input is not recommended or normal practice, although it may work in this instance.
Also recognize you have an inversion on the input.
Max.

The course is ECAD but this isn't for a course. I practice PLC programming on my own time so this is just part of a project I've made up for myself. The software side of things I'm pretty good at, the electrical...not so much.

As far as sink current goes I'll make sure I do all the calculations before I actually connect anything to the PLC. Right now I'm just learning/working in multisim to get the circuit "working".

 

It is a good idea to let us know up front if this is a practical application or a hypothetical case.
This way it can be answered in the correct manner.
IOW, whether this is a real world scenario or an academic exercise.
Max.

 

It is a good idea to let us know up front if this is a practical application or a hypothetical case.
This way it can be answered in the correct manner.
IOW, whether this is a real world scenario or an academic exercise.
Max.

Yeah this is a learning project. Going to read up on transistors now, I need a better understanding.

 

Here is a little something on PLC sink/source also.
Max.