Reading a voltage

Now the tricky part is i dont have an analog input on my Micrologix 1500

i need to read a voltage so that i can see both what actual voltage the power source im powering from currently is and also to determine how bright it is in a room

You can try with a voltage to frequency converter, if you have a fast digital input you can use it, otherwise i have no other idea.

Welcome to the forum.

Is the voltage source highly variable such that you need to know its actual voltage? Or do you only need to know if it is above a certain threshold.

If the latter than a limit relay will do the trick. Check www.dataforth.com www.actionio.com ad www.phoenixcontact.com for some sources.

If it is the former then you will probably need to bite the bullet and add an analog input and an appropriate signal conditioner if the voltage is something other than 10V.

The more info you can provide the better we can answer your question.

You're going to have to convert it externally to digital. So, I don't see the point in trying to do this without an analog input. At some point it has to be converted, why not use a 'proper' analog input. Any savings you think you might gain in using digital inputs that you have will be consumed by the effort it will take to build some kind of kludge (that won't nearly work as well).

If it's a DC-input model of MicroLogix 1500, you could use a voltage-to-frequency converter. I like the 8500 and 8600 series from Calex, as well as the products from Sensorpulse.

Otherwise, you'll need to add a 1769 bus expansion module, like the 1769-IF4 .