The Pakscan P3 modular control system from Rotork Controls provides a wireless network for Rotork valve actuators, eliminating wiring in new installations and retrofits. The system operates on the 2.4 GHz frequency and has a line-of-sight operating range of 70 meters indoors and 1,000 meters outdoors.

Developed for the oil and gas industry, traditional two-wire technology was adopted by the wastewater market in the 1990s, says Howard Williams, vice president-controls. “Before then, many plants didn’t have a centralized control room. A valve operation involved someone walking up to the valve and pressing a button to actuate it. If you wanted to control the valve from a remote location, you had to hardwire the actuator.”

In 1985, the first two-wire control system replaced these wires with a twisted shielded pair of cables running in a daisy chain configuration from actuator to actuator. This allowed full operational control of each actuator in the loop and gave access to asset management data stored within each actuator. “Basically, the plant operator could see what was going on inside the actuator from the control room,” Williams says.

A wireless system eliminates the expense of wiring. “At plants that have existing hardwired systems and are undergoing renovation, the savings from a wireless system can be significant,” Williams says. “Existing buried conduits are often corroded. The control wiring is beyond reuse and the cost of excavating and replacing is high.”

A plant with an existing Pakscan two-wire network can add a wireless segment to control any new actuators by installing a wireless module to communicate with any new wireless-equipped actuators. The new actuators will operate wirelessly alongside the existing wired unit.

The wireless system uses a series of antennas to relay data from the field unit inside the actuator to the master station. The system works as a mesh network, which means multiple actuators communicate through multiple paths, providing redundancy. “If the normal traffic route between two actuators is blocked, the network finds another path through neighboring actuators to continue communications seamlessly,” Williams says.

Web pages built into the system enable control room operators to access and extract information such as actuator data logger and configuration files, observe changes in the operation of the valves, and eliminate downtime. Multiple security measures protect the system against malicious and accidental interference. 585/247-2304; www.rotork.com.