Mitsubishi FX1N DI reacting on negative state

[VLADOAP]

Hello,

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!

 

[itsmoked]

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

 

[thebard3]

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.