A delicate balance

OGS AND CATS, LIBERALS AND CONSERVATIVES, Red Sox fans and Yankee fans. Some groups share a common space but just won&rsquot get along. Ever. A common view in our industrial networking space seems to be that factory and plant floor controls engineers and arch-rival IT professionals are polar opposites, too.

Until recently, these groups passed like ships in the night and the systems they captained did too. Plant and factory control systems running on hardy, hard-wired I/O networks went one way, mostly trafficking in isolated machine data and occasionally communicating machine to machine. Meanwhile office, enterprise data and telecommunications systems went another, running on fast, but delicate data networks that managed the flow of information across the organization. If the front office needed operating data from the factory, it came through the door on a clipboard via SneakerNet or was keyed into an office network workstation at the end of the day.

Then open-standards computing, Windows-based architectures, OPC, and Ethernet began to overrun the factory control network engineer&rsquos domain. In an ever-growing number of companies, much of the data in the machine and process system networks now needs to flow into the office, often in real time. 

The factory people didn&rsquot like outsiders messing with their networks. The IT group viewed factory and plant floor networks as archaic undisciplined balls of data-carrying wire.

But the mandate to make everything work in harmony is unavoidable. This is a true work-in-progress. After all, it&rsquos likely you&rsquove overheard some of the frustrations bubble up from the ranks of each group:

• &ldquoThe IT folks don&rsquot appreciate that this is where our company makes money. They impose arbitrary standards that delay installation and support, then go home at 5:00 and we are left trying to solve the problem.&rdquo
• &ldquoThe plant staff act like cowboys and don&rsquot appreciate that we have procedures that must be followed to protect the integrity of our computer systems.&rdquo
• &ldquoThe IT staff is so paranoid about hackers that they won&rsquot make any changes that violate the configuration standards established for the office systems.&rdquo
• &ldquoThey only were concerned about the plant floor when they installed that system. The databases are a mess and it is almost impossible to translate it to our accounting system.&rdquo
• &ldquoThey just don&rsquot understand our business.&rdquo

In this article we&rsquoll explore what plant people view as the big issues and challenges, how that matches up with the perspectives of IT counterparts, and exactly where the differences are and, most important, where common ground can be found. This isn&rsquot easy, but there&rsquos reason to be optimistic.

Vive la Difference
IT departments constantly battle the ever-increasing need to provide more computing power and software applications, and the resulting demand for more bandwidth. A poorly designed enterprise systems easily can cripple heavily burdened communications channels. The IT department must be convinced that a new enterprise automation system will not adversely affect the rest of the communications traffic.

The plant floor operates in real time, often on a millisecond-level scan cycle. PLCs are always talking, and when polling is used to process this chatter—as is usually the case—too much traffic is created on the network, at least from an IT perspective. The traffic can slow the entire network, clogging it with a continuous flow of information.

When dealing with mission-critical ops, the factory floor needs much more reliability than IT, and &ldquonot only fewer outages, but faster recovery, along with more visibility of entire network,&rdquo says Gary Workmann, principal engineer of plant floor networks for the controls, conveyors, robotics and welding division of General Motors (www.gm.com). &ldquoDifferent system architectures are sometimes needed to satisfy IT vs. control needs.&rdquo

Control system downtime cannot be tolerated, stresses David Glanzer, director of technology development at the Fieldbus Foundation (www.fieldbus.org). &ldquoEnterprise computing is mostly supervisory or accounting-related and can tolerate some downtime without affecting production or safety,&rdquo says Glanzer. &ldquoBecause of this difference the plant floor personnel will want to control access to network equipment and software changes. IT personnel are not used to asking anyone for permission to make changes.&rdquo

It is imperative that plant control systems be protected. &ldquoFrom a network perspective the technical issues for the plant floor are fairly straight forward,&rdquo says Chris Rogers, manager of electrical and process controls at Boise Cascade&rsquos (www.bc.com) Boise Paper Solutions in Boise, Idaho. &ldquoSome time is required working with the IT folks to develop a network standard that includes the plant floor network and the business network. The biggest issue is system security.&rdquo