Communication between S7-400 and Omron PLC

[JesperMP]

If there are 900 m between the two PLCs, then an Ethernet based solution cannot go directly via copper cables.
You would have to go via fiber or connect via a plantwide network. To mix your system with a plant-wide network can be a disadvantage or an advantage. You would have to coordinate with the local IT department. Consider what happens when there is maintenance on the plant-wide network. Can your system accept if the connection is lost ?

At 187.5 kbps Profibus can reach 1200 m.
As I see it, Profibus is easy and inexpensive.
Profibus cable costs 10 DKK/m, fiber much more.

 

[Henny]

And before buying anything first download and install the configuration software and/or ask you local dealer if the Omron driver you need is availible.

Kind regards
Henny

 

[Hubert12]

If there are 900 m between the two PLCs, then an Ethernet based solution cannot go directly via copper cables.
You would have to go via fiber or connect via a plantwide network. To mix your system with a plant-wide network can be a disadvantage or an advantage. You would have to coordinate with the local IT department. Consider what happens when there is maintenance on the plant-wide network. Can your system accept if the connection is lost ?

At 187.5 kbps Profibus can reach 1200 m.
As I see it, Profibus is easy and inexpensive.
Profibus cable costs 10 DKK/m, fiber much more.

The cable is already there and the customer wishes specificaly to use it for communication, so there is no issue with that.

 

[Hubert12]

Hello Hubert

If i understand you correctly then you want both plc,s to do profibus and then use modules to convert profibus to ethernet?

If you costumer allows aditional hardware for the communication between the two systemens then another idea would be the use of a red lion data station.
In this station you have a lot of PLC protocols availible and you can map data from one protocol to another.
Has been succesfully used in the Netherlands also for communication between Siemens and CTI plc,s

The advantage is that you don,t have to buy plc hardware.

http://www.redlion.net/products/industrial-networking/communication-converters/protocol-converters

This is a link to a dutch website where you can see some screenshots.
http://prodek.nl/page-cti-redliondatastation.html

The configuration software is for free.
Price of a red lion data station according to Prodek is about 700 euro.

Kind regards
Henny

I have talked with them, they will find out the best solution and get back to me with an offer. Thank you.

 

[JesperMP]

From the 1st post:

They would like to have a direct communication between PLCs

The solution with Profinet/Profibus gateways or a Redlion HMI as a gateway are not "direct". Besides, the more links there are in a chain, the more problems there can be. If the customer seem to have a firm idea what he wants, I would clear it with him before you go ahead with any of the gateway solutions.

So as I see it, under the requirements that an existing ethernet connection must be used, and the connection must be as "direct" as possible, then only the Modbus TCP option is open.
Too bad that the S7 CPU isnt a PN CPU, since the Modbus library is far less expensive for PN CPUs than for CPs.

 

[Henny]

Hello Hubert

I agree on Jesper about the direct communication.
I also agree on Jesper what he said about having separate networks for IT and Production.

Experience learn that things start with a simple connection and if people see that it works they rapidly wants to connect and add more devices to the network. Then problems arise and a separate network for production still needs to be installed with more impact on things because production must keep running and afterwards you regret that you didn’t start at the beginning with a separate network for production.
But the decision is up to you and/or customer.

If you decide to go for the modbus way and don’t want to make use of the free function blocks I stated in post #9 then first read the manual about this driver and see if your CP supports its.

http://plc4good.org.ua/files/02_materials/modbus/Open_Modbus_TCP_for_NCM_CP_English.pdf

Kind regards and success.
Henny