You must see what you're doing to do a good job. For automobile drivers, this means good eyeglasses and clear windshields. For process applications, it means thoroughly deployed and maintained sensors, comprehensive and reliable networking, and well-organized and coordinated data to maintain safety, optimize operations and maximize profit. These methods have often moved from plant floors to field applications, but lately they've also been moving to fields of wheat, corn and other crops.
It might seem like grains and seeds are just inert commodities, but they respirate just like the plants they come from—each a tiny process system, really. As a result, their moisture and other critical factors must be carefully monitored and efficiently managed during handling, storage and processing to preserve their vital characteristics, yield and value—and avoid hazardous conditions and potential explosions.
To help its agricultural and industrial customers achieve these goals, system integrator Lakeland Companies in Minneapolis, Minn., develops and deploys an array of process controls, networks, equipment and services. The 64-year-old firm started as an electrical distributor in 1952, but it's always maintained a tradition of identifying new market opportunities, so over the years it added system integration, panel building, control design, software programming and startup/commissioning capabilities—and even started new companies to help. It's been a Control System Integrators Association member for 10 years, and presently works in the grain handling, seed treating, grain processing, ethanol, biodiesel, railroad and oil/gas pipeline industries.
Proper crop care
"The challenge has been that control technologies are changing rapidly, but they still go into panels that are supposed to last for 25 years," says Mark Spindler, CTO at Lakeland. "To handle increasing yields and more grain, covered ground piles and bunkers are used, but they must be closely monitored to avoid spoilage and other problems. So we've developed a solution that uses wireless temperature probes to communicate with panels located next to the piles, which then communicates to the cloud via cellular and wireless technologies. Once this data is on a server, if temperatures are trending too high, an alert can go from the cloud to the applicable customer, who can log onto a web page displaying all of that pile's temperatures and trends (Figure 1).
"These piles typically have six to 10 fans each, and their performance can be boosted to move more air under the cover or into the bunker to reduce grain temperature. These fans are also used to suck down the tarps and secure them when it's windy, so our system also monitors local wind speeds with an anemometer and connects to National Oceanic and Atmospheric Administration data, which lets users dial down their fans when it's calmer, saving about $200 per month for each fan."
Developed by one of Lakeland's cornerstone firms, this remote data gathering and control solution is named the Extron Ground Pile Monitoring System, and it continues to be enhanced after it was launched about four years ago. It's based on an updated version of Extron's BusMux temperature multiplexers, and is named the Extron Grain Management System (Figure 2).
"The original BusMux was invented to replace older multiplexing technology for temperature and hazard monitoring in grain elevators. They checked bearing temperatures, and helped detect misaligned belts on conveyors," explains Spindler. "While the older technology could update thousands of temperatures, the multiplexer took 10-12 minutes to update, which was too long for many users. In addition, replacing this older technology with PLCs and I/O with Class 2, Div 1 ratings made them too costly for monitoring larger areas. So we were challenged to develop a better solution, and we came up with a BusMux that can monitor 168 sensors in one rack with a 1-second update time. More recently, BusMux was upgraded again to handle 672 sensors. It's also intrinsically safe, and now the Extron Grain Management System can wirelessly monitor BusMux racks, ground piles and wireless grain temperature cables."
To deliver true grain conditions and enable better decisions, Lakeland's remote sensing and monitoring system also needed to overcome the often high ratio of inaccurate or broken sensors in grain handling, especially because the company and its users are adding more sensors in more locations. Fortunately, the system's networking functions can provide data on broken or misconfigured sensors to help them get fixed sooner.
"We audit grain elevators as a service to check if they're working properly, and over the past three years we completed 70-75 of these audits," says Spindler. "We found that, of the 200-300 sensors on a typical grain elevator, it was common for 5-30% of them to have sensing issues, such as sensors that were not reading correctly, alarms that weren't set right or conveyors that were not interlocked properly. Whether we're dealing with thermocouples, RTDs or digital devices, older systems aren't as good at dealing with grounded sensors. The worst case is seeing two thermocouples shorted together because the sensors will average their temperatures—perhaps 70 °F and 300 °F—and will indicate there's no danger when there is. A lot can happen with sensors, such as misconfiguration when a user maps it into a PLC, but does it backwards, which replaces one indicator for another."
To achieve more accurate and reliable remote sensing, Lakeland relies on another of its companies, RRAMAC, which has been monitoring railroad track operations for about 10 years, such as the inrush current on blowers used to warm track switches at switch points typically miles apart on sections of track. It checks if bearings seem to be failing so repairs can be scheduled, or checks propane tank levels so they won't run out. However, where RRAMAC used to send data via satellite and cellular networks, its wireless sensors now deliver information, including video, over Internet and the cloud to its servers.
Tighter seed treating
"Railroad monitoring was RRAMAC's entry into remote monitoring, but now it's using these Internet, cloud and server technologies for many different kinds of applications and OEMs that want to monitor equipment they sell to let them know when they need service," adds Spindler. "For instance, RRAMAC's technology remotely connects seed treating machines that accurately apply chemicals by monitoring their weight. This usually involves blending about six chemicals. However, some users have unique requirements, such as a seed treatment that has a short shelf life that needs to blend chemicals on demand, and apply them at treatment facilities set up for the farmers."
Traditionally, farmers would roll up to their local seed treatment facility and receive the right chemical mixture and measured amount based on the recipe they ordered. In recent years, these seed treatment facilities added PLCs, HMIs and cellular Internet connections, which means they're subject to the same alarms and faults as typical plant-floor processes.
"In this case, another of our companies, Control Assemblies, teamed up with RRAMAC to develop an Internet and cloud-based enterprise control system to provided required traceability of the chemical system," adds Spindler. "It's been available for about five years. Basically, we provide the remote monitoring infrastructure and controls, including Proficy iFix software from GE Automation and Controls', and cellular modems from Red Lion. We also developed interfaces with Microsoft .Net, and use SSL to secure the cloud communications. As a result, chemical deliveries are documented by SAP software, and this information goes from XML to the cloud, its users, their machines and other equipment. This lets seed treaters say how much they need of each chemical, know they have the right amount coming, and verify it by scanning a barcode when it's delivered."
Serving up cloud flexibility
Over the past five years, Spindler reports that Control Assemblies' enterprise control system for seed treating has improved chemical handling by users, allowed much tighter recipe control, and improved maintenance at local seed treating facilities. "However, the biggest benefit of remote monitoring and asset management on the Internet and cloud is its ease of implementation for our users,” he explains. “This is a pay-as-you-go software as a service (SaaS). If an OEM wants to monitor their equipment, it used to be a huge project and cost hundreds of thousands of dollars, but now we can get up and running in a very short time, and they don't need to maintain the PLCs or systems.
"For example, if a ground pile monitoring site has a problem and needs to make a change or enhancement, then it's more likely they can do it today without added cost because we're already taking care of the field hardware, and much of the other equipment and software is based on servers, so we don't need to do a lot either. For example, we can apply a software patch one time, automatically download it to the remote sites, and then everyone on the system across hundreds of sites can use it. We also maintain webpage interfaces to all these ground pile, seed treating and other applications, and they're on servers too, which means less cost and fewer headaches for us as well."
In the future, Spindler expects even more devices will participate in the Internet of Things (IoT) because many devices still don't have the internal microprocessors and Internet connections to join in. "We do a lot of this now with software and brute force, but I believe that soon we'll see more controls and components connecting seamlessly like plug-and-play Bluetooth in most cars," he adds. "SCADA systems will run as part of controls displayed on web pages, controllers will run in the cloud, and only I/O will be in the plant."