Allen Bradley Micro 800 Private / Plant Network Transversal

[freddie.b]

Hi all, I have problem that I could do with some help with:

I have a setup consisting of an Allen Bradley Micro 820 controller, Panelview 800 and a VSD, all communicating on a private Ethernet IP subnet as an island.

The above setup is part of a mobile machine that is able to be moved around our company.

What I would like to achieve is to add a network device that is able to bridge / route between the private machine and plant level networks. I would like this to happen by having the plant level network DHCP server assign one single dynamic IP to the bridge / routing device.

Essentially what I want is a setup that works akin to a Compactlogix 5380 configured in Dual IP mode (one port for the machine network and one for the plant network).

The end goal would be to be able to move the machine between different sites / subnets on our company, with the ability for it to be plugged in to the local subnet, if needed, mainly for support purposes. It would also be useful to be able to see the assigned dynamic IP somewhere on the HMI.

Any ideas greatly appreciated!

Many thanks,

Fred

 

[iDoWell4]

Hey Freddie,

I've used the 1783-NATR for a similar purpose. One ethernet port is for the local address and the other is for the plant address. You have to configure the device to route the local ip address though to the plant address. If you do this, make sure you set up that IP as a gateway on the Plc, HMI, and VFD.

 

[drbitboy]

Welcome to the forum (for posting, anyway)!

Which devices on the private ("island") network need to communicate with the plant-level network?

In which directions are connections initiated? i.e. from island to plant, or vice versa, or both?

What kind of power is available to the bridge/router device?

What kind of network connection is available to the bridge/router (twisted pair, wifi, radio, dialup, 10baseT, 10base2, 10base5, etc. )?

What type of environment does the mobile machine operate in (industrial, commercial, office, etc.)?

The Stratix, as mentioned earlier is probably the best choice, but you need to consider at least these issues in it's configuration.

 

[Ken Roach]

This is a totally normal application for a small DIN-rail mounted 24-volt powered network router. A-B sells some that are expensive but easy to set up, other vendors (Moxa, Sixnet, A-D Stridelinx) are less expensive.

The easiest way to set this sort of thing up is 1:1 Network Address Translation (NAT) in which the device has multiple WAN addresses that "map" to multiple LAN addresses.

But your application where you want a single dynamically-assigned WAN address is a more normal "router" sort of application. The devices that want to access the PLC and HMI from their network connection on the WAN side will need a VPN, VLAN, or ordinary static route to the LAN configured by you or the IT department.

For my own use in similar applications, I use a software-defined virtual LAN that is brokered through the Internet, called ZeroTier. Forum member Phil Buchanan turned me on to it, and it's really useful once you get used to it. I run it on routers and Raspberry Pi's with OpenWRT Linux-based firmware.

The challenge of showing the dynamically-assigned WAN address on the HMI screen is an interesting one. Typically that information would be accessed through an embedded web-server, or via Simple Network Management Protocol. But neither the Micro 820 nor the PanelView 800 has the ability to easily be an HTTP or SNMP client.

If you do choose a router that runs Linux, especially the popular OpenWRT firmware, there are probably methods of setting it up as a Modbus/TCP server or even running a Python script that sends its configuration data to the Micro 800 controller.

 

[freddie.b]

Hey Freddie,

I've used the 1783-NATR for a similar purpose. One ethernet port is for the local address and the other is for the plant address. You have to configure the device to route the local ip address though to the plant address. If you do this, make sure you set up that IP as a gateway on the Plc, HMI, and VFD.

Thanks for this, but it won't work with Dynamic (DHCP) addressing on the plant side?

 

[freddie.b]

Welcome to the forum (for posting, anyway)!

Which devices on the private ("island") network need to communicate with the plant-level network?

In which directions are connections initiated? i.e. from island to plant, or vice versa, or both?

What kind of power is available to the bridge/router device?

What kind of network connection is available to the bridge/router (twisted pair, wifi, radio, dialup, 10baseT, 10base2, 10base5, etc. )?

What type of environment does the mobile machine operate in (industrial, commercial, office, etc.)?

The Stratix, as mentioned earlier is probably the best choice, but you need to consider at least these issues in it's configuration.

Thanks, I have been "lurking" around for many years, but can usually find the answers I'm looking for by googling, so rarely need to ask.

The Controller, VFD and HMI all need to intermittently communicate with the Enterprise network for fault finding / diagnosis purposes. This will be via a standard CAT5/6 patch lead, which will only be plugged in when needed.

The machine works in a lab environment, but as we have labs in different locations, it will be moved between locations (and hence different subnets on the same corporate enterprise network).

For normal operation, the machine does not need to communicate with the outside world.

So basically, the port on the Enterprise side needs to take a dynamically assigned IP address (DHCP), as and when remote support is needed. This then needs to be displayed on the HMI, so the local operator can relay this to myself, so we can "go online" across the corporate network to fault find.

Any device should be 24VDC powered in this application.

 

[freddie.b]

This is a totally normal application for a small DIN-rail mounted 24-volt powered network router. A-B sells some that are expensive but easy to set up, other vendors (Moxa, Sixnet, A-D Stridelinx) are less expensive.

The easiest way to set this sort of thing up is 1:1 Network Address Translation (NAT) in which the device has multiple WAN addresses that "map" to multiple LAN addresses.

But your application where you want a single dynamically-assigned WAN address is a more normal "router" sort of application. The devices that want to access the PLC and HMI from their network connection on the WAN side will need a VPN, VLAN, or ordinary static route to the LAN configured by you or the IT department.

For my own use in similar applications, I use a software-defined virtual LAN that is brokered through the Internet, called ZeroTier. Forum member Phil Buchanan turned me on to it, and it's really useful once you get used to it. I run it on routers and Raspberry Pi's with OpenWRT Linux-based firmware.

The challenge of showing the dynamically-assigned WAN address on the HMI screen is an interesting one. Typically that information would be accessed through an embedded web-server, or via Simple Network Management Protocol. But neither the Micro 820 nor the PanelView 800 has the ability to easily be an HTTP or SNMP client.

If you do choose a router that runs Linux, especially the popular OpenWRT firmware, there are probably methods of setting it up as a Modbus/TCP server or even running a Python script that sends its configuration data to the Micro 800 controller.

Thanks Ken, this is a very insightful / helpful post.

On reflection though, it might be simpler and less expensive to spec a low end 5380 controller instead. We could then use it in Dual-IP mode, with port A1 set to DHCP. I could then read this ports IP configuration with a periodic MSG instruction, condition it and display it on our HMI. Port A2 would then be used for the local (HMI and VFD) network, and the IP addresses would be the same for each machine produced.

Thanks again for your help.