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“Generally speaking,” says Concept’s Taylor, “the days are gone when you used tools from test and instrumentation companies that were specifically developed for diagnostics. Nowadays, most control application development takes place on PC laptops, and the programming software comes with diagnostics that aid in debugging and tuning the software.”
According to Taylor, Ethernet is, for now, an exception to the above. “In our experience, there are no real good laptop diagnostic programs available yet for Ethernet that allow you to get in the network without affecting the network. Special tools such as those from instrumentation vendors such as Fluke are designed to non-invasively monitor the network.”
Traditional scanning programs such as Ethereal (open-source) or EtherPeek (commercial) require a fair degree of training before using them and getting useful information, and, the general consensus is that they are probably better used by an IT expert.
Brian Singer provides fair warning. “I don’t recommend [these tools] without some serious training behind them,” warns Brian Singer of Rockwell Automation, the chairman of the ISA99 committee. “I’ve seen people crash lots of production processes because they thought they could get away with doing a full network scan using these tools.”
Other commercial tools are becoming available that can help plant and IT engineers. According to Komarek, network management software knows what devices are present on the network and which are missing, and it presents pictorial information (See Figure 3). Engineers can use network management software to set the IP addresses, determine network status, and configure each device. Network management software is never required, but as networks get bigger and bigger, the software makes it much easier to maintain the network.
FIGURE 3: VISUAL NETWORK ANALYSIS
This network software pictorially identifies industrial Ethernet nodes and paths. It reveals duplicated IP addresses, cable faults, broadcast storms, device lock-ups, and more. Source: NetworkVision (Click image to enlarge)
Training for Troubleshooting and Maintenance
System integrators are a good source of training for troubleshooting and maintenance. But the level of training depends on the user. “We go into plants where the customer has no internal electrical programming capability,” says Wahl. “In that case, he’ll be looking for us to provide a flexible solution that doesn’t have to be changed in the future.” On the other hand, he says, if they have some maintenance electricians who are relatively savvy, they want to be sufficiently trained to own the solution.
“DeviceNet and ControlNet solutions will be more challenging than the Ethernet solution, so they will need more training on the non-Ethernet networks,” concludes Wahl. “You have to think like a PLC engineer. But, I think EtherNet/IP is a good entry-level network. It will cover most applications and do it more economically.” There are applications that will need a non-Ethernet solution, for example 40 or 50 VFD drives. That, according to Wahl, is a perfect DeviceNet application.
“If you’re dealing with issues like security, downtime or critical expansions, too much is at risk to not bring in someone with a specialization in the area,” counsels Schneider’s Lewis.
Form a Study Group
If it’s an Ethernet-based fieldbus and sharing plant data is important to the enterprise, then help might be as close as the IT department. Levine suggests that integration should be done by the IT department and the control department. Both departments should have questions for the other department.
This level of cross-training raises vital awareness of the issues on both sides of the firewall.IT should be made aware that the control network might be sensitive to heavy traffic loads (broadcast storms, etc.). Discuss using VLANs. Ask what type of data that will pass between the two networks. Determine the type of access to the controls network provided to personnel in the IT group. Will everyone be able to access the control network? Discuss the type of access to the IT network provided to control network devices and personnel. Discuss all potential connections to the Internet. Do any control devices require a hole punched in the firewall so that it can be remotely accessed via the Internet?
Cross-pollination training matters—from the beginning of the project. “For the migration to the new control scheme, we meet bi-weekly to iron out lines of demarcation, and overall network architecture, says Navistar’s Llewellyn. “This is probably the best, most productive time I have spent in a meeting. It pays to have your IT department and your engineering staff understanding the needs and concerns of each other to make sure you don’t start down a path that ultimately has to be abandoned. Left purely up to one group or the other, the results would have been disastrous, but by meeting in the middle, before the infrastructure is ordered, we have been able to head off a large portion of the issues without spending any money.”
This list is a starting place to find network training services and tools. It is by no means complete, since many companies offer products or services in all three categories.
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