Hello,

I'm trying to control access to a PLC by the PLC. We have a controller that can be accessed by an external network (at work) that needs to be isolated under most circumstances. The PLC has it's own LAN network with several HMIs and modules, and what not. The external connection is through a Cat 5E cable connected to the business network. Right now we have one of those manual switches on it where if you want to give access, you have to go back in the server room in the back of the building and turn a knob on a box- the box has a female Cat 5e slot for one end, and two slots for the other- one of the others is empty, so you switch to the empty one when you want to no access or switch to the one that is plugged into the PLC if you want to allow access.

I hope that makes sense. What I want to do is use a digital output from the PLC that can activate a similar interrupt switch of some kind. I can't seem to find any products like this out there. Does anyone know where I can find something like this? Or maybe even make one? Thanks!!!

 

Maybe a cheap 5-port switch like this one: NETGEAR 5-Port Gigabit Ethernet Unmanaged Switch (GS105NA) - Desktop or Wall Mount, and Limited Lifetime Protection (cheap in dollars, but I have used many, they are well made).

They run from 12V at about an amp, so if you just turn the power on and off to the switch with a relay, you can cut off access or restore it.

 

Maybe a cheap 5-port switch like this one: NETGEAR 5-Port Gigabit Ethernet Unmanaged Switch (GS105NA) - Desktop or Wall Mount, and Limited Lifetime Protection (cheap in dollars, but I have used many, they are well made).

They run from 12V at about an amp, so if you just turn the power on and off to the switch with a relay, you can cut off access or restore it.

Genius! I think that is exactly what I will do!! Thank you.

 

Actually, the mechanical switch is a very good approach because it will keep hackers out of your PLC while it is off. That may be a very big benefit. So while the suggestion from Yaakov is correct and should work, the present setup with a manual switch is more secure, if you always remember to switch it off when not using it.

 

Hello,

I'm trying to control access to a PLC by the PLC. We have a controller that can be accessed by an external network (at work) that needs to be isolated under most circumstances. The PLC has it's own LAN network with several HMIs and modules, and what not. The external connection is through a Cat 5E cable connected to the business network. Right now we have one of those manual switches on it where if you want to give access, you have to go back in the server room in the back of the building and turn a knob on a box- the box has a female Cat 5e slot for one end, and two slots for the other- one of the others is empty, so you switch to the empty one when you want to no access or switch to the one that is plugged into the PLC if you want to allow access.

I hope that makes sense. What I want to do is use a digital output from the PLC that can activate a similar interrupt switch of some kind. I can't seem to find any products like this out there. Does anyone know where I can find something like this? Or maybe even make one? Thanks!!!

Google for "Cat6 ethernet A/B switch" and you'll find some that can be remote controlled via serial or management network.
Their kinda pricey though...