NAT in industrial networks solves a real addressing problem and quietly creates three new ones. This is the buy or readdress decision, fully costed, from a live plant deployment.
Most plants meet network address translation the same way. A new machine arrives, the builder has assigned an addressing scheme that has nothing to do with the plant, and somebody decides whether to renumber every device in that panel or put a NAT device in front of it.
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Learn more at Joltek:
- IP Addresses in Industrial Automation and OT Networks:
https://www.joltek.com/blog/ip-addresses-industrial-automation-ot-networks- Modern Plant Network Requirements for Manufacturing:
https://www.joltek.com/blog/modern-plant-network-requirements-manufacturing- Plant Floor OT Networking:
https://www.joltek.com/blog/plant-floor-ot-networking- IT and OT Architecture and Integration:
https://www.joltek.com/services/service-details-it-ot-architecture-integrationReaddressing looks cheapest on a quote and is not. Renumbering a panel needs connectivity to the PLC, the HMI, the drives and the servo drives, and in a Rockwell Automation environment that means a licensed copy of Studio 5000 or RSLogix, and very likely FactoryTalk View ME. Plenty of small and mid sized plants have nobody on staff who can do that and then verify every device still communicates.
Then there is warranty, which rarely comes up in the engineering discussion and always comes up later. It sits with the original machine builder and is commonly void once the equipment is modified. If your team renumbers that panel and the builder can no longer reach it at the addresses in their own records, you own that conversation.
The third problem catches technically strong teams. Putting everything on the plant network means deciding what traffic belongs there. A PLC and an HMI are usually fine. Hundreds of drives are a grey area. Vision systems publishing images to a server are not, and safety systems add their own polling load.
NAT is the other route. It sits between the panel and the plant and translates one to one. The PLC at 192.168.1.10 inside the cabinet is published to the plant as 10.10.10.100, the HMI at .11 becomes .110, nothing inside the panel changes, and the builder's scheme survives. Rockwell Automation sells the 1783-NATR for this, higher tier Stratix switches can do it with the feature licensed, and vendors including Moxa build industrial switches with the capability.
This is not a free translation layer. You only translate what you explicitly map, so a drive with no entry is genuinely unreachable from the plant side. An engineer at a desk running RSLinx can reach the PLC and cannot open that drive in Connected Components Workbench. Standing at the panel, they need a different address range on their laptop, and an IT provisioned machine may not let them change it. The workaround is that the NAT device usually holds an address on both networks, so you can add a temporary entry, do the work, and remove it afterwards.
The hardware runs from roughly $1,000 to several thousand dollars per device. On top of that you pay engineering hours to build and document every entry, and you maintain two address schemes per machine for as long as that equipment runs. That spreadsheet becomes load bearing, and every contractor you bring in has to be told what they are walking into.
Neither route is wrong, but neither is only about one panel. Once a plant starts down the NAT path it tends to spread into every machine that follows, so this is a standard you are setting, not a purchase you are making. Choose on purpose, write the choice down, and make sure the next person who opens that panel knows which one you picked.
Timestamps
0:00 The plant with a NAT device in every machine
3:10 What network address translation actually is
4:10 Why machine builders hand you an addressing problem
6:40 Option one: readdress every device in the panel
9:00 What readdressing really costs in licences and hours
10:00 The warranty exposure nobody budgets for
10:40 Which devices actually belong on the plant network
12:22 Option two: how NAT sits between the panel and the plant
14:30 The laptop problem: plant side versus equipment side
16:45 When an IT provisioned laptop cannot reach the drive
17:25 The temporary translation entry workaround
18:30 What NAT costs to buy and to keep running
20:50 How to make the call
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