Water flow alarm system

This is a community-service project built by Instrumentation students at BTC. We are using an Automation Direct "Click" PLC to measure municipal water flow to a housing association which has experienced problems with pipe leaks. When a pipe leaks underground, they don't know about it until they get a huge bill from the city at the end of the month. This system will receive pulse signals from a flowmeter (1 pulse per gallon of water consumed) and calculate flow rate, signaling an alarm if the flow rate exceeds a pre-set value. The PLC communicates to a touch-screen "HMI" panel over a radio link, about 1000 feet of distance separating the flowmeter/PLC assembly from the maintenance shop where the touch-screen unit will be located. The radios are spread-spectrum 900 MHz units, communicating serial Modbus data between the PLC and HMI panel at 9600 bps. The PLC unit has a battery back-up unit connected, so it will continue to run for hours in the event of a power outage. At the time of this video, the unit is being "burn-in" tested in our lab, to detect any potential problems prior to the installation. This is why the assembly looks so messy: everything is patched together on a rolling workbench for the test, using a signal generator and a small relay to simulate the pulse output of the flowmeter.