Wireless Speed Control of Effluent Treatment Pond Aerators

The Problem:

Six aerators operate off of Variable Frequency Drives (VFD) that need to be controlled from a single Dissolved Oxygen (DO) sensor.  The sensor outputs a 4/20 mADC signal proportional to the dissolved oxygen in the treatment pond.   Without a wireless solution six signal wire runs of 200 ft to 1000 ft would be required at a cost of $40 to $50 per ft.

The Solution:

A single DR9011 Wireless Transmitter was installed at the DO sensor location.  The wireless transmitter required 24 VDC power, that was also available for the sensor.  Using a small bulkhead omni-directional antenna the output of the DO sensor is simultaneously transmitted to all six VFD’s.  The VFD’s receive the 4/20 mADC signal via a DR9021 Wireless Receiver installed in each of the VFD cabinets.  The DR9021 Wireless Receivers outputs an isolated 4/20 mADC signal proportional to the 4/20 mADC input of the DR9011 Wireless Transmitter.

Total Cost of Wireless Installation:

$4550.00 (Including Wireless Transmitters/Receivers and Antennas)

Estimated Cost of Wire Runs (Without Wireless):

$45.00/ft x 4000 ft = $18,000.00