Connect an ethylene sensor to a 24-volt direct current (DC) power supply. The ethylene sensor has a current-to-RS-485 converter. Plug one end of its cable to the sensor port and the other end to either the battery pack or the 24-volt DC power supply connector port at the back of the 24-volt power supply.
Attach the 24-volt DC power supply to an electric outlet using a power cable. Connect one end of the cable to the 24-volt DC supply and the cable's other end to the electric outlet.
Turn on the DC power supply. The ethylene sensor should show zero reading if no ethylene is in the air.
Connect 3 feet of polyethylene tubing to the ethylene sensor's nozzle. The tubing should match the nozzle's size. If it is a little too big, attach the tubing to the sensor nozzle with cellophane tape.
Open an ethylene can, and let it evaporate into one plastic bottle without the bottle's screw-on cap in place. After about two minutes, screw the cap onto the bottle.
Unscrew the cap of the plastic bottle you filled with ethylene, and insert the end of the polyethylene tubing into the bottle. Observe the reading on the ethylene sensor's digital meter. The reading will be a number, such as 2, 20 or 28, indicating the concentration of ethylene in the plastic bottle in parts per million
Remove the tubing from the ethylene-filled plastic bottle, and dip it into the neck of a second plastic bottle. Check the reading of the ethylene sensor meter again. The reading should be much lower for the second plastic bottle than for the ethylene-filled bottle.