Wireless Access Allen Bradley

Hello!

I'm currently trying set up our department with wireless access for the PLC network on our site. When connecting to smaller local network's i.e. up to 5 plc racks, connection is fine on the wireless access point. However, when go into the whole plant network I,e 80 ip address all static assigned, the wireless signal keeps dropping.

What I mean by this is, plug in the D-Link Linksys as a wireless access point, go into RSlinx and detect all networks, some appear some don't. Ones that do appear are random in connection i.e. one second live, next second red x on the process emblem.

Any idea what cause could be? LAN is fine, just when try connect wireless

Do you have any multicast traffic on your control system LAN ? If you don't have your Ethernet switches set up properly to constrain multicast using IGMP Snooping, your WiFi is probably being saturated with multicast.

A quick sniff with Wireshark will show you right away if you have multicast traffic on the network.

With regard to your PC; be sure you aren't trying to run a wired network and a WiFi network at the same time. RSLinx (and many, many other software packages that use TCP/IP) does not deal well with multiple networks that have overlapping subnets.

I use a router setup as an access point every day to connect to my plc networks. I just make sure to use the router/access point as a wireless hub, by only plugging in the network to the "hub" ports not the internet port (I never use it). I set a static ip on my wireless adapter. And connect. Never had any issues. Make sure what ip your device has and it is not used on the network. I actually set my A/P for a totally different subnet as not to intefere. Make sure DHCP is not on router/ap.

I've heard about that slightly before with multicast. Something I'll look into actually. The site network is a bit of a bodge really as in add a bit here and there over time so may not be fantastic for wireless yet.

Robo77 yes thought this was the issue at first, but like said tried on smaller networks and works fine on them, but when on the network as a whole (number of the smaller networks tried on hooked together) signal keeps dropping like it picks a certain module up that drops the connection down completely.