Siemens S7: How do the IO modules talk to CPU?

Mas01

Member
Join Date
Oct 2020
Location
Leicester, England
Posts
1,105
Apologies for the basic question (thus far I've only worked on Mitsubishi Q PLCs). I've been given this S7-1200 PLC to get some familiarity...

1. If I were to add another card/module (e.g. an 8-way analogue input module), how does it talk to the PLC? I ask because the Mitsubishi PLC has a special backplane rail with pins/sockets - when you insert the module , the pins connect and the new card talks to the PLC....in the photo the Din rail is just bare metal. How will a new S7 module communicate with the CPU?

2. Presumably, the ladder logic is written to the PLC's CPU via the ethernet port circled right?

Thanks in advance!

S7.jpg
 
Last edited:
1, the card would sit to the right of the processor. There's a port there (if the processor accepts expansion cards) which will allow the backplane bus to communicate. There's a sliding button on the card itself which actions the ocnnection, I believe.

https://www.manualslib.com/manual/1453610/Siemens-S7-1200.html?page=60

2. Yes.

Thanks - this is what threw me - the CPU I've got does not support expansion...there's no sliding cover thingy , like in the manual you linked to.
 
If its a S7-1211 there is no expansion port on the right of the PLC, only expansion you can have is the small SB expansions that plug into the cover that has the sticker in your photo.

For example there is the SB1223 with 2 digital outputs, but there is also an SB with an analog input, but you wont be able to put 8 analog inputs in that PLC, unless you use remote PROFINET IO.
 

Similar Topics

Hi First post here! I admit I am not too used to handle interrupt OBs in Siemens. I have a customer who has been buying a standardized solution...
Replies
4
Views
218
Can we use a central Active Line Module to supply with 540VDC power, Sinamics Double Motor Modules installed in other cabinets many meters away...
Replies
2
Views
1,329
So everyone knows how to inhibit a module in studio or rs5000 I need to do the equivalent in tia portal 15. Need to run some test code but my...
Replies
4
Views
2,459
I have a offset printing M/C it's using a siemens S5 115 cpu with 14 analog interface modules . now the interface modules only showing error...
Replies
8
Views
2,788
Good day All, We are using a Desoutter CVIL II Controller for a project. It is currently connected from the RS232 Port of the Contrroller to a...
Replies
1
Views
2,724
Back
Top Bottom