Dear All ,

One of CPU 1212 DC/DC/DC  is not powering up at all and LED not getting on . There is supply at CPU Power terminals 24 V DC and I am not seeing the MCB tripping . Don't know what is wrong out there .

If any one has any suggestions or  reasons for it , Please let it know guys .

Thanks

Sarabjot Singh Manku

Hi,

1.look for any short circuit across the power supply terminals of plc . 

2. is it a new one ?

3.if positive negative is swapped it will not power on pls check the positive negative too??

4.and if by mistake it is powered with ac VDR might have failed need to be send to plc??

ssmanku1699

Dear All ,

One of CPU 1212 DC/DC/DC  is not powering up at all and LED not getting on . There is supply at CPU Power terminals 24 V DC and I am not seeing the MCB tripping . Don't know what is wrong out there .

If any one has any suggestions or  reasons for it , Please let it know guys .

Thanks

Sarabjot Singh Manku

Did you physically measure with a multimeter that the PLC do receive 24V?
Also.. make sure the signal ground is actually connected to the negative port of the 24V power supply.

Dear all ,

Can anybody tell me , What will happen if there is short circuit at the CPU 1212 DC/DC/DC power terminals ?

Does it have short circuit protection ?

As per his manual http://datasheet.octopart.com/6ES7212-1AD30-0XB0-Siemens-datasheet-12175106.pdf

they have mentioned something like this :-

Short-circuit protection         0.0000000000000000E+00

This indicates that Incase there is a short circuit , It will directly impact the PLC and its modules like the way I am looking at it.

What do you think Guys ?

Thanks

SSManku