Tag Archive for Wireless

Monitor Flow and Level Wirelessly at Remote Sewage Lift Stations

Monitor Flow and Level Wirelessly at Remote Sewage Lift Stations

Back in the late 1980’s a local city municipality had six lift-stations wired underground directly to their Wastewater Plant located a few miles north of Daytona International Speedway. However, in 1995 a forest fire burned the entire surrounding fields which destroyed the Level and Flow sensors and the underground wires going to the wastewater plant were melted and rendered useless.

Cost issues have been a concern for this more rural municipality. They were searching for a more economical and cost effective way to retrofit the three lift stations than reinstalling all the old hardwired systems.

Over the years, all six of the lift-stations have been repaired and upgraded. However, they have only hardwired three of the main lift-stations back to the Wastewater Plant using a data acquisition system.

The city would like to tie the remaining three lift-stations into their data acquisition system by using Wireless Telemetry. By doing this they will be able to monitor two 4/20 mADC signals coming from a Flow and Level sensor at each of the three remaining lift-stations.

The decision to use Wireless was made to help alleviate the destructive issues from the aforementioned forest fire as well as help maintain the integrity of the system given Florida’s high winds (upturned tree roots), excessive high level ground water, and encroaching metropolitan development.

All three lift stations are located about 1,000 feet apart from each other deep into the forest. However, there is a 40 foot wide clearing next to the lift-stations which the city keeps mowed as an access road to each lift-station.

DR9011 With 3 Element Yagi Antenna

DR9011 With 3 Element Yagi Antenna

In order to test the effectiveness and durability for the new proposed wireless system one of the remote non-wired stations was configured in the following manner:

·        3-Element, 8 dBi Gain Yagi Antenna was installed on a small 10 foot tower at one lift-station

·        A DR9011 wireless transmitter was installed in the existing enclosure along with the Flow and Level sensors producing the 4/20 mADC signals.

·       A DR9021 Wireless Receiver was mounted approximately 3000 ft away at one of the main lift-stations.

DR9021 Wireless Receiver

DR9021 Wireless Receiver

·        The 4/20 mA signals out of the DR9021 Receiver were wired directly into the existing data acquisition system to be sent back to the Wastewater Plant for monitoring.

The system has been running trouble free for over two years (2012) and the two other wireless systems are due for installation when time and funds are available.

Note: The lift station supervisor said that by using the Wilkerson Instrument Company wireless system they will be saving the City over $25,000 for the 3 installations.

Wireless Control of Life Support System in an Exotic Aquarium for Show Animals

Wireless Control of Life Support System in an Exotic Aquarium for Show Animals


Park engineers have an application sending a 4/20mA signal from an ORP (Oxidation Reduction Potential) sensor to a Control Room approximately 500 feet away.

The ORP sensor is used to electronically monitor the amounts of sanitizer and other chemicals in the water, before it enters the large holding tank.

Rain or shine, a ladder is climbed to the top of a pump house building several times everyday to take readings. This posed a safety and health risk to the operator as well as only provided sporadic measurement cycles.

The EPA requires monitoring of this chemical system for both human and animal safety.

More Info: Frequency Hopping Spread Spectrum Technology

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The ORP monitor where the reading was taken is in a hard to reach location at the top of a pump house on the side of the tank.

Due to a large amount of sidewalks and other obstacles, it was not cost effective to run wires from the sensors to the Control Room.


Checking the 500 foot line of sight between the Transmitter and Receiver locations indicated there was a 50 foot elevation difference. The check of the antenna path also indicated there was a large building near the Receiver. There are also several trees in the antenna path.

More Info: How to calculate your antenna needs


DR9011 With 3 Element Yagi Antenna

DR9011 With 3 Element Yagi Antenna

Use a 900 MHz Band Transmitter (DR9011, 2 analog and 4 switch inputs) at the top of the building to monitor the 4/20mA signal from the ORP sensor.

The DR9011 was installed inside a NEMA 4X housing. A small 3” high 2.1dBi gain vertical antenna was mounted on the top of the NEMA 4X housing.

Use a 900 MHz Band Receiver (DR9021, 2 analog and 4 switch outputs) at the LSS Control to receive the data coming from the DR9011 Transmitter.

This unit was installed inside a pre-existing control panel. Along with a wall mount 3 element directional Yagi antenna (8dBi gain) to the top of the LSS (Life Support System) Control building.

The use of the Omni directional antenna at the sensor end allowed the signal to be transmitted across a wider path. In using the Yagi antenna at the receiver side, the install crew was able to choose the best location and path for pointing the Yagi antenna.

The trees and building posed difficulty by either blocking part of or potentially causing a reflected signal in the Fersnel Zone. The Yagi helped eliminate this due to its narrow beam width.

This system has been reliably sending data since June 2007.


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