PPI and MPI differences

[redeemer]

Hi, I'm looking into using a Siemens PLC in a new application, and there's something that I couldn't quite understand. What is the difference between a PPI and an MPI network connection? The information that I got from the catalogue suggests that in both networks multiple "stations" can be connected on the same bus. Is this correct? and what are the differences between the two. In my application I'm going to connect a PC (running Citect) to a PLC and and inverter and a Panel. The network should permit: The PC to collect data from the PLC, and maybe the inverter as well. The PLC to control the Inverter. The Panel to collect data from the PLC. Is this possible using PPI? or MPI? Regards

[JesperMP]

Hello redeemer The following I believe is not possible with neither PPI nor MPI. The PLC to control the Inverter. For Siemens drives, like Micromaster4xx, and the like there are two main protocols to control the drives: USS and Profibus DP. Both are possible with S7-200 and S7-300 (may require optional modules). For other manufacturers drives, PPI and MPI are not commonly used if at all.

[ChanThien]

what Jes said are completely correct. You can MPI to connect Pannel with PC or PLC but Inverter can't. You can use Profibus to connect Inverter with PLC siemens. However, you need to look for dirver of Inverter.Hope you to be successed.

[wnicholson]

Be careful. The last time I did any investigating the 200 could only be PB slave. Can the drive or the PC be the master in your situation? If not then you should consider a 300.

[Crossbow]

S7-200 can only be a slave device on a Profibus network. S7-300 or another PLC is required to master the network. Only brick I've ever seen that can master Profibus is the Mitsubishi FX3U.

[JesperMP]

Ooops. You guys are right. I knew there was a master module for S7-200, but upon checking it, I see that it is for ASi not Profibus. Thanks for putting me straight.