Can any one help me

[mshifa]

Hello,

I am a late beginner with plc, sorry for that.

I have a siemens s7 1200, 1212c Ac/DC/Relay type.I started a simple program and wired the plc using a breadboard,: input, mini bush button and output led light.The wiring seems good, because i see input led light branding when l push the push button but it does not initiate the output. But within the program by forcing the input it works. what went wrong?

Thanks in advance

[collinsd70]

Hi mshifa.

Firstly welcome to the forum.

My initial guess is that you have the wrong Input Address in your program? Can you double check the input address matches your physically wired input?

If this is all OK maybe check your voltage supply, it may be sufficient to illuminate the LED but not necessarily enough to close the input relay.

Otherwise please attach your code and maybe a photo of your wiring..

 

Regards

Daniel

Edited February 27, 2019 by collinsd70

[mshifa]

THANKS FOR THE REPLY

I hAVE JUST WIRED  EXACTLY  LIKE THIS WITH 24 VDC FROM PLC  TO THE INPUT AND EVEN USING SIEMENS SIMULATION SWITCHES, IT DOES NOT INITIATE OUT PUT, THE ADRESSES ARE EXACTLY THE SAME THAT WHY THE LED BRANDS ON I0.0 AND THE CODE IS I0.0. tHE ONLY DIFFERENCE I HAVE IS THE OUT PUT VOLTAGE, I USED 9Vdc.

 

[dekor]

Hello mshifa,

You just give us the most important hint: voltage is 9V DC.

9V is not considered as HIGH logical level.

9V is not LOW but also is not HIGH.

Just change to 24V DC and it will work.

[Joe E.]

The way I read it is that he's using relay outputs to switch the 9V. If they're really relay outputs, the voltage shouldn't matter (unless it's way too high, of course).

Can you post a screenshot of the PLC code while it's executing?