Burned up MPI new 315-2 DP doesn't work

[Agrajag 0]

Hello, We are having a communication problem with a S7 315-2 DP CPU. First, a little history: History: We needed to get online to this PLC and could not. We are connecting a field PG MPI port to the MPI port on the 315-2 with a direct (pin-to-pin) cable and the PG interface settings are all set for MPI communication. This usually works. In an attempt to work through the original problem, we removed the connector (the one that we were piggybacking on) from the CPU MPI port and connnected the field PG MPI port directly to the CPU terminal. We then smelled burning electronics and shut off power to the system. We are quite certain that the MPI port on that CPU is smoked as it doesn't smell like it should anymore. Response: So, we removed the MMC (memory card) and transferred it into a new 315-2 CPU that was then installed into the rack in the same fashion as the original card. Now, we are still unable to get online with the new CPU. We have tried memory resets from the MMC and have checked the MMC program (directly inserted MMC into PG card reader). When we connect directly from PG:MPI<->CPU:MPI we cannot find any available nodes and we get "no other active partner can be found" errors as if nothing is connected at all. We have tested the PG at another siemens network and it works OK when using the MPI port. Questions: Do you have any advice? Should it be OK to connect directly to the CPU MPI port from the PG MPI port with a direct cable? What is the procedure to restore the CPU to default factory settings? [found in section 9.5 of manual, https://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&objId=13008499&objAction=csOpen&nodeid0=33519671&nav0=index&idxSrc0=cpu+313c?=en&siteid=cseus&aktprim=0&extranet=standard&viewreg=WW ] THANK YOU ALL VERY MUCH! Edited 13 Jan 2011 by Agrajag

[JesperMP 2]

Yes it should be OK to connect directly from MPI/DP port on the PG to the MPI port on the 315-2DP. I guess that the problem caused the damage was voltage differences between the PG and the PLC. That is a classic one. --> Always use the same power source for PCs and PLCs when connecting them together. Or run the laptop on batteries. Not sure what goes wrong for you. If you use a new MMC in a new CPU and the PG works with another PLC, then it should go OK. I would have done the following tests, after the damage occurred: 1. If the DP port on the 315-2DP was configured for DP, then attempt to connect PG and 315-2DP via DP. Note: This will not work if you have reset the CPU to factory settings. 2. Connect via another PG to the damaged 315-2DP if possible. First via MPI, and if the DP port was configured then via DP. 3. insert a new MMC card in the damaged 315-2DP CPU, and try to connect again. Note: This is only possible via the MPI port. 4. Exchange the damaged 315-2DP CPU, insert the existing MMC. 5. Use a new 315-2DP CPU and a new MMC card and connect with the PG. Note: This is only possible via the MPI port. If this does not work, then the MPI/DP port in the PG is also damaged.