Astec and Customers Gain Benefits from Safety Networks

-- Control Engineering, 9/13/2005

To access a free white paper from Siemens detailing the evolution and business advantages of machine safety, click here.

Safety networks have been making original equipment manufacturers and their customers not only more safe, but more efficient. A case in point is Astec Inc., an OEM that designs, manufactures, and markets continuous and batch-process hot-mix asphalt facilities and soil remediation equipment.

Design, installation, training, and efficiencies related to safety equipment on Astec machines have improved recently with the company’s incorporation of safety networks, suggests Mark Harned, vice president of controls for Astec.

“We see a need for both AS-Interface (AS-I) and Profisafe,” Harned says, two networks represented by AS-International and Profibus Trade Organization. “Each network has its place. AS-I is a bit bus, and the other’s a higher-level bus. We use Profisafe as the backbone of our safety network. Soon we will use ASIsafe [AS-Interface Safety at Work], which allows ease of installation and simplifies wiring,” Harned says. Safety networks avoid the need to bring all wires back to the motor control center, and the need to try to lock out each device, he says. “It’s tied right in there to monitor each individual point.”

The new system was easy for Astec engineers to learn and deploy, Harned says. “We’re pretty comfortable with PLCs, and we know industrial automation networks pretty well. Our engineers got up to speed quickly. Siemens gave us good examples, and they’re more than willing to help. When we train, customers need to understand new capabilities of the system.”

Using safety networks, Harned says, is a change “culturally and in practice. Customers quickly found out on the first machine that they didn’t have to use their voltmeters to troubleshoot everything. They could actually monitor from a computer and know which station was causing the problem. All they had to do was look at the operator interface. We programmed it so you could see all the functions, specifically down to which node was causing the problem, and down to the individual e-stop. This definitely sped up our installation.”

Harned adds that “overall safety functionality has absolutely made our company more competitive.” In a recent presentation Harned made to two new clients with Astec’s chief executive officer, discussions included Profisafe functionality. “It was a large part of our presentation on a new crushing machine. Users like the simplicity of what we’re doing and the ability to monitor every safety stop and every safety device on the machine. They see benefits of less down time right up front.”

Before using safety networks, Harned says, Astec had dozens of hard-wired e-stops connected to multiple safety relays controlling multiple zones. Safety stops routinely took 20-30 minutes to troubleshoot. Following the implementation of safety networks, e-stop wiring decreased thousands of feet, wiring time decreased by hundreds of hours, and troubleshooting became fast and easy on the same panel as the control. Astec also is adding more circuits to the safety system, taking advantage of drives and other devices being placed on the safety networks, and continuing to lower costs and improve machine safety and controls.

Harned made the comments related above in a recent “Simplified Safety” Webcast, which can be accessed by clicking here.

To access a free white paper from Siemens detailing the evolution and business advantages of machine safety, click here.