Maximum length for MPI=50m, but...

le meusien

Dear all,
I have a OP77A to connect on my MPI network but this one is over 50 meters for sure. And I've seen this on Siemens site:

"The maximum line length in an MPI sublet is 50m for a baud rate of up to 187.5 Kbaud with non-isolated interfaces. Between nodes with isolated MPI interface the line length of a segment can be up to a maximum of 1000m, provided the transmission rate of 187.5 Kbaud is not exceeded"

But, what does it means "1000m for nodes with isolated MPI"? It means I'm quiet with my OP or I've to add a repeater?

 Hi, When you said "the maximum line lenght in MPI is 50m (non-isolated)", this is the distance between nodes or the total distance of the network MPI?

I have 12 PLC and I need to connect them, the distance between PLC to PLC it's 20 m, I have in total 220m in all the network, it is posible this solution?? Please help me.

Wizard

le meusien

Dear all,
I have a OP77A to connect on my MPI network but this one is over 50 meters for sure. And I've seen this on Siemens site:

"The maximum line length in an MPI sublet is 50m for a baud rate of up to 187.5 Kbaud with non-isolated interfaces. Between nodes with isolated MPI interface the line length of a segment can be up to a maximum of 1000m, provided the transmission rate of 187.5 Kbaud is not exceeded"

But, what does it means "1000m for nodes with isolated MPI"? It means I'm quiet with my OP or I've to add a repeater?

Dear le meusien,

Yes, you are right, when you have non-isolated interface, maximum MPI cable length is 50 mtr.
See this link:
http://support.automation.siemens.com/WW/view/en/37627

So it depends on the used CPU. When you can change MPI port into an Profibus port it is an isolated interface (cable length might be 1000 mtr.) But when you can not change MPI port into Profibus port it is a non-isolated interface (cable length 50 mtr.)

Best regards,

Wizard

Hello lester roque,

can you describe your hardware a little bit more?

It's easier to help you if there are more informations, then it's also necessary, because the solution which we can suggest is very different and very dependent of the hardware.

Maybe you can think about Profibus, Profinet or?

regards
CaOd

Hi, I have 12 PLC (314-1AG14-0AB0) and this PLC have a MPI non-isolated. I need to connect all the PLC's to a MPI network. The distance between PLC to PLC is 20m, in total 220m in all the network MPI.

My question is, its posible my solution. In the post I read "the maximum line lenght in MPI is 50m (non-isolated)", this is the distance between nodes or the total distance of the network MPI?

I don't want to use DP or PN because I should buy another PLC or CP.

Hello,

probably you don't have other choice. Maybe you can put OLMs with FO between each or as is needed due length, or simply try that. This kind of network (OLMs with FO) I got via MPI but between 2 houses about 200m.

Sublet meens part of the network, so I think 50 between nodes.

https://www.hmisource.com/otasuke/files/manual/gpproex/new/device/data/sie_mpid.pdf