Portable measurements are reliable enough to tell us when a heat exchanger is experiencing problems, but they may not be the best solution. Finding the quickest and most cost-effective way to get a handful of new measurements is the goal at hand. So what's the best method? John Rezabek, process control specialist for ISP Corp., Lima, Ohio, says over the last 20 years, hazardous-area-capable multiplexers have become commonplace, but if your plant doesn't have them deployed, I/O bus extenders and modules, and wireless are also options. In this article from sister publication Control, Rezabek evaluates these various measurement options and makes a case for why wireless is the leader in the race to the finish line.