The Problem:
The operator of this municipal wastewater plant needed to monitor the process information from around the facility on a SCADA system located in the control room of the central building.
The process information comes from (2) 4-20 mA transmitters and (6) digital status signals scattered around the plant that are a good distance away from the central building 
including a chemical storage tank 
, open channel flow 
, aeration building blower status 
, pump station pump status 
, and compost blower status 
.
Hard wiring all these transmitters would mean running hundreds of feet of physical wires throughout the plant which would be too costly for the budget and take too much time, something the plant manager did not want to do.
The Solution:
With future expansion in mind, the solution was to install a PDW90 point to multi-point wireless system consisting of one PDW90 base station and eight PDW90 field units. The field units were easy to install right out of the box, and with the 24 V power available around the plant, made it even more convenient to get the units up and running in no time!
To make sure there was a good connection between the base station and the field units a PDA10 wireless survey tool kit was used, which allowed the installer to test the signal before installing the units.
PDW90 Field Unit Installation at Storage Building
PDW90 Field Unit Installation at Open Channel Flow
PDW90 Field Unit Installation at Aeration Basin Blowers
The rugged field units were mounted directly at the transmitter sites, each being independently ranged to the base station.
The range of the PDW90 units are 1 mile line-of-sight outdoors and 500 feet indoors. Although, many of the field units had obstructions to the base station, the antennas were mounted up high to avoid most obsticles and all signals between the units and base station were succesful.
PDW90 field units with NEMA 4X, IP68 aluminum enclosures were used at this plant, but the field units also come in stainless steel which are even more resistant around salt water or in harsh chemical environments like this wastewater plant. The enclosures contain plenty of room for field wiring connections and an optional two Form A (SPST) relays module.
PDW90 Base Station with Attached Antenna Inside Building
4-20 mA and Digital I/O go to the SCADA system
The PDW90 base station was installed indoors in the central building. Initially, the installers were going to run a conduit outside the building to connect the antenna to a remote location, but near the window they had good enough signal strength from inside the building even though there was not a line of sight to any of the field units.
Finally, the installer connected the (2) 4-20 mA and (6) digital outputs from the PDW90 into the SCADA system that displays all the information.
Learn more about the PDW90 wireless products used in this wastewater application and more below:
