Reading Voltage

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Fairly new to PLC. I've created a system that can move an arm via Servo Motor and drive as well as operate some solenoids and power switches. Customer is now looking to be able to read voltages in case there is a fault, for troubleshooting.
I'm using Automation Directs 2000 series and I cant find an analog input that will read above 10V.
I have 24V and 12V. Is this a case where I need to read the current instead and can I then program some math in to convert it back to a voltage reading or is there some sort of step down device.
I thought the answer was a signal conditioner to read current and output voltage but i seem to be wrong.

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There are a few options depending on exactly what you want.

1) Many power supplies come with a 'Voltage OK' signal built in. You could use this turn ON or OFF a standard input. You would have to view the specs on the OK signal of the power supply. Usually it would be a relay contact but could possibly be NPN or PNP.

2) If you already have power supplies without this signal then you could use the output power to energize a relay. Then use the relay contacts to turn ON or OFF a standard input.

3) If you are interested in the current (Amps) draw, then find a Current Transducer. They come in many sizes and outputs. You would have to measure or calculate your current draw to size it properly. Most of them are designed for large current draws so it may be difficult to find something under 10A or so. The output can be your standard 0-10V or 4-20mA for your analog input.

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