Hello dear all,

I have a problem about S7-300 PLC and memor card. We have a machine with CPU 319-3 PN/DP PLC. Machince was working normally. We want to change Analog Input type of module 0-5 V to 4-20 ma for 12 Analog input.

Firstly I took a backup from CPU 319-3 with siemens USB/MPI adapter. Backup process was succesfully. After that I opened HW Configuration from backup in STEP 7 - Simatic Manager and I changed AI type in AI Module properties page. Then compile and save. After that , I downloaded hw configuration with stop mode. Now all plc leds blinking and communication drops. I can not connect the PLC. When power off and put out the MMC , I can connect the PLC. But when I insert the MMC , all leds blinking. I try it with 2 new MMC. When I put in new MMC first time, there is no problem. Then I donwload program to new MMC , after that all led blinks again. I tried it two times but nothing solved. I have 3 MMC now , but all of them crashed I think.

Also we tried memory reset from siemens procedure with MRES button. Nothing solved.

How can we solve this problem? Is there anyone help us?

Thank you.

Hi,

Let's clarify some points:

1. Did you put the CPU in STOP mode before download the modifications, or CPU passed STOP after download the modifications?

2. Did you see there any messages during download?

3. When you insert the MMC - the CPU led STOP will start blinking? it is correct? 

3. Did you did a memory reset?  

Definately, CPU will need a "good new" card. Please check the following link https://support.industry.siemens.com/cs/ww/en/view/29801950.

BR,

hristo

Hello,

next ideas. You  said that you've reconfigured all inside HW and did download to CPU. But what about code cfg due changes inside HW? All code inside pLC working looks like with all previous HW expected AI module, addresses so you need also change all code depended to changes with the new AI module, in my opinion. I don't want to say that LED flashes due this but your description says nothing about that changes inside pLC code also. LED flashes can indicate something wrong cfg of PLC or wrong reset procedure after insert new MMC.