I have an ethernet flex i/o module that is inside a rolling pump skid. The pump skid can be connected to three separate machines which each have their own PLC (A-B 1756-L62). The three machines were recently connected through a switch in an auxiliary solution delivery system. Now, when the pump skid is connected to one machine, all three machines can see it and possibly start it. I was playing around with using a router to use the IP/MAC filtering to prevent the pump skid module from being seen by the other two machines.

I am not an network expert, but I was wondering if this could even be done. Before turning on any filtering, I have been trying to ping a PLC through the router (with no success). I played with the router configurations so that I can ping the router on the WAN side and the LAN IP address from the WAN side. I think there might be some port forwarding that I might have to do, but I haven't the foggiest what ports the Control logix 1756-ENBT uses.

- note that the WAN side of the router is a fixed address.

- the gateway setting in the 1756-enbt is set for the address of the LAN side of the router.

- RSwho gives nothing.

- can not ping through the router.

The A-B modules mention gateways, but I'm not sure what gateway they mean? Also, I am trying to keep costs down so I wanted to avoid fancy programming by enabling/disabling the i/o module in each PLC and buying really expensive switches.

So, what I'm really asking is has anyone done anything similar to this?

Thanks,
Tom

 

Tom,

For EtherNet/IP protocol communications, the C*Logix uses TCP Port 44818 and also UDP Port 2222 (maybe TCP Port 2222, also?).

Forwarding those ports thru the router may help.

 

Tom

I think you'd better use hub switch from cisco rather than router then configure the switch with three VLAN. VLAN means virtual lan and this mean you have three separate lane for the three machine and no one has the permission to see each

Thanks,

 

Thanks, but I couldn't get it to work using these ports. I thought I might be able to at least see the web page of the 1756-ENBT, but nothing.

I think I will consider a different approach because I am running out of time for this particular problem. Perhaps I will try dynamically switching the AENT/ethernet comm module (in my spray skid) enable property on/off based on some switch or manual input signal in the SCADA or maybe on the skid itself.

I think I understand the Cisco switch concept, but I'm not sure that is in the budget.

Thanks for you help with this problem!