Hey everybody,
I am very new to the networking and how it works. I am an Electronics Engineering Technology Major and this kind of topic is not discussed in our degree. I hope I can find some help. I have read over many manuals and implemented Cisco labs as well as spent much time googling trying to figure out how to do what I am trying to accomplish.
So I have two Cisco 2950 switches. I am working with Siemens Simatic 505 PLC’s that are communicating through the 505-CP1434TF H1 module. Before implementing any of the following I had both PLC’s connected directly through each other’s H1 modules and they were communicating without any issues.
I started out by setting up one switch. From factory defaults I created Vlan 99 and gave it all of the ports using the interface range fa0/1 - 24 command and assigned it an IP address of 080.006.011.1 and subnet mask of 255.255.255.0. I also gave it a default gateway of 080.006.011.1. My two PLC’s both are configured with IP addresses that are within the IP address that I assigned to the switch. Once I got the switch configured I plugged in my PLC’s and they worked flawlessly.
On my second 2950 switch I implemented the same exact configuration as switch 1 except making its IP address 080.006.011.2. It has the same subnet mask and default gateway as switch one, it is also configured using vlan 99 for the ports. I tested the second switch by plugging both of the PLC’s into it and it also worked flawlessly.
I began running into trouble whenever I started trying to have only on PLC per switch with the switches hooked together through port 24. So PLC A was plugged into switch 1 on port 1 and PLC B was plugged into switch 2 on port 1 and the two switches were linked together through port 24. Simply doing this without changing any of the configurations did not allow my PLC’s to communicate to each other.
I have read a lot about putting the port into trunk mode in order to get two switches to communicate to each other so I tried changing port 24 on both switches to trunk mode and still did not see communication.
Is there something that I am missing? Is there an easier way to implement something like this? My end goal is to be able to have a few more PLC’s per switch all communicating to each other as well as a PCS station, it is a type of operator station that Siemens created for their line of PLC’s. I would also like to get to the point where I can sit at a computer and remote into the PCS station.
Anyways if anyone could maybe give me some guidance that may be more in laymen’s terms I would greatly appreciate it. Or even point to me a manual or lab that would create a similar setup. I used the Cisco 2.5.1 lab to create the configurations on the switches as well as attempting to understand the 3.5.1 lab.
Thank you for all your help.
Chase
