FX2N S/S terminal missing

[Eduard 0]

Hi, I need a bit of help with an FX2N 48 MR Mitsubishi PLC. I have a customer that has an imported machine that is running an FX2N PLC. The S/S terminal is linked to 0V so thart the inputs switch on 24Vdc. The PLC was damaged and he sourced a new PLC with program from the supplier. I installed the PLC but found that there was no S/S terminal. Only a 24V and a common. The inputs switch on 0V. Can anybody help with how I would convrt this PLC to switch on 24V???? Many thanks Eduard

[Inntele 60]

What is full name of PLC base module?

[donny 0]

Hi Eduard It seems that you have a Japanese spec. FX2N 48MR. I had to replace FX2N 48MR-ES/UL ( Euro Spec. ) with FX2N 48MR ( Jap.Spec ) with no S/S. I rearranged I/P & O/P to switch 0V & 24V respectively. Some work but worked OK. I was unable to think any other method except rearrange I/P & O/P as it was a rush job. Hope above would have some help. donny

[JRoss 84]

If it doesn't have the S/S terminal, then it is most likely the Asian version of the unit, which only accepts sinking inputs (switch on 0V). You'll need to find a North American version of the PLC, which are the ones that can handle either sinking or sourcing. If you don't have very many inputs, then you could look into signal conditioners.

[Eduard 0]

It is a FX2N-48MR and yes it is from China

[Eduard 0]

Unfortunately I am stuck with this PLC as it has the program in it. I am unable to replace all the sensors as it is too costly. Is there any hardwiring that can be changed? Thanks for your help!!

[Inntele 60]

No, it's impossible to change hardware inside the PLC or to use sink inputs if the sensors in the automation system are P-N-P transistor type. So there are two possibilities: 1. To demand the replacement of PLC type of the supplier. 2. To upload the program from Japanese spec. type of PLC, to buy the PLC of World spec. type and to download the program into it.

[Juancho 0]

If you are looking for a cheaper option, you can use an input expansion module FX2N-16EX-ES/UL, this is a 16 input sink/source module and you can connect it to your FX2N PLC. Take in mind that you have to re-asign the inputs to the new ones.

[donny 0]

Hi Eduard There are 3 other possibilities if you are familier with electronics. 1. Use NPN transistors to switch plc inputs via 0V ( use sensor o/p to switch on the transistor and supply 0V to plc i/p). 2. Use logic gates to convert 24V ( sensor o/p) to 0V (invert o/p signal ). 3. Or simply switch on low power relays or ssr s via sensor o/p s and use contacts to supply 0V to plc i/ps. This way you can still use 0V to switch plc i/p s and sensors or other external o/p s use 24V. All methodes are simple , very low cost , easy to constuct and you can still keep the new plc. It is also easy to change switching mode eg.Sink or Source. donny Edited 9 Feb 2011 by donny

[Eduard 0]

[donny 0]

Hi Glad to hear you are happy with solutions to your problem. Let me know if requre further help. Will post necessary circuit dig.s etc, if you get stuck. donny