Convert M251 rack to distributed perifery

[m_turk]

If the program on the existing Modicon CPU wont do anything but exchange the IO via Modbus TCP, there will be no need to change the program at a later date.

If you need to install any new hardware to the existing Modicon PLC, then it is better to bite the bullet and replace everything for new S7-1500 hardware right away.

It kind of depends how many modules, inputs and outputs there is.. And I think you are forgetting the rewiring and new schematics, dimensions change etc.. Not needed if he just replaces the PLC with a distributed periphery module..

 

[Lare]

It kind of depends how many modules, inputs and outputs there is.. And I think you are forgetting the rewiring and new schematics, dimensions change etc.. Not needed if he just replaces the PLC with a distributed periphery module..

But if M251 CPU is allready doing only mapping IO to modbus, then there is no need change to distributed periphery module.

M251 PLC modbus range is also easier to understand than distributed periphery module's which addressig changes if you add new modules between old installed.

 

[m_turk]

But if M251 CPU is allready doing only mapping IO to modbus, then there is no need change to distributed periphery module.

M251 PLC modbus range is also easier to understand than distributed periphery module's which addressig changes if you add new modules between old installed.

Why would he ask how to "Convert M251 rack to distributed perifery" if it was allready doing it?


I personally would keep the M251 because I know how to program it. But if their client doesn't want to have a program in M251 then the periphery module is the other choice ..

 

[Lare]

Why would he ask how to "Convert M251 rack to distributed perifery" if it was allready doing it?


I personally would keep the M251 because I know how to program it. But if their client doesn't want to have a program in M251 then the periphery module is the other choice ..

Actually OP's original ask was how to add M251 I/O to Siemens 1500.

M251, M221 or BEIP, there is even profibus card to M251 but I would also keep original M251 CPU as I have licensed version allready for that and make modbus TCP coms from 1500.

 

[m_turk]

Actually OP's original ask was how to add M251 I/O to Siemens 1500.

M251, M221 or BEIP, there is even profibus card to M251 but I would also keep original M251 CPU as I have licensed version allready for that and make modbus TCP coms from 1500.

To me it seemed like he knows how to handle S7-1500, but doesn't know the M251..

Well, however he meant it, he knows all his options now..