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Mitsubishi FX1N DI reacting on negative state

Mitsubishi FX1N DI reacting on negative state

Mitsubishi FX1N DI reacting on negative state


I have some troubles with FX1N plc.
The problem is that digital inputs react only when there is negative state ( 0V and not when there is +24V). I’m using Gx developer software with ladder logic. What may cause that problem? I’m new in PLC programing.
Thank you!

RE: Mitsubishi FX1N DI reacting on negative state

You need to lookup and understand "source and sink logic". That will flip the state of an input, or output, for that matter. Also, a lot of newer PLCs will allow both with a single model of I/O card. It's up to the user which way they wire it as to whether a 0V or 24V input is seen as an active input.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Mitsubishi FX1N DI reacting on negative state

Assuming your input module is for a sinking type input, you may need to use a pull-up or pull-down resistor to set the input voltage when the input device is off. Something link a 5Kohm resistor tied to the appropriate (high or low) voltage will usually work.

Brad Waybright

It's all okay as long as it's okay.

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