How to use the Flowline Ultrasonic Liquid Level Sensor
Live demo showing you how to setup and use an ultrasonic liquid level sensor in simplex, lead/lag and duplex modes.
In part one of this video, we looked at Simplex mode where the Flowline Ultrasonic Sensor controls just a single motor or a single valve. This sensor supports two other modes – Lead Lag and Duplex. Note that both of these modes assume that both motors or valves are on the same end of the tank. They are either filling or emptying the tank. Given that we have two pumps, we select the mode that we want. We’ll start with Lead Lag in this example. Relay Failsafe – same as before – we’ll use everything off. Switch/Alarm Configuration – because we are using two motors, there are only two outputs remaining for us to configure. We’ll use the 1Hi, 1 low configuration. Hysteresis – we’ll use same 2” we had before. Loop failsafe – we’ll choose hold last value. And what’s our output level at empty? We’ll make that the 4 mA again. I’ve already filled in the blanks with the numbers from that Simplex example we did in part one. The only difference is there is no Hi two alarm anymore – just one high alarm – and that extra signal is used to turn on this Lag motor. In Lead Lag mode the lead motor turns on whenever the fluid hits the ON level, the Lag motor turns on when the fluid hits the Lag level. Both motors shut off as the fluid rises and hits this off level just like in simplex mode. This is great for the situation where you have a pump that easily handles a normal load. But during peak times it can’t quite keep up so you need to supplement it with another pump to keep up with demand. Let’s set our Lag level at 12 inches which is below the ON level but still above our alarm. Let’s try it. Write the configuration to the unit. I didn’t mention it before, but the USB programming adapter powers the sensor during programming so make sure you don’t connect the Flowline sensor to its power source AND the USB adapter at the same time. Use one or the other. Looks like we are ready to go. We don’t want to write another configuration. And we are good. As the fluid level falls to the ON or Lead level we see the lead pump turn on, and if the fluid level continues to fall we see the lag pump turns on. Both turn off at the OFF level. Alarms work the same as they did before with the hysteresis. If we change this over to Duplex Mode, everything is identical to Lead/Lag with one exception. Just like Lead/Lag, one motor turns on when we hit the ON level and the second motor turns on when we hit the Lag level. As the level rises, both motors turn off. Next time the fluid level lowers, the second motor turns on first and the first motor turns on second. That’s the key point with Duplex: Each time the level falls to the on level, the sensor alternates which motor turns on. That way you get even wear on both motors. In this setup like this you would usually want to have the motors be the same size, where as in Lead Lag you could get away with the Lag motor being a different size – usually smaller to save cost and to just supplement the lead motor. Let’s try that real quick – We’ll write that out to the sensor. And again, I’m going to disconnect the USB programming adapter before I apply power to the sensor. So let’s try it real quick. If the level falls below the ON level this motor turns on and if we fall below the lag level, the other one turns on. So far so good. That’s just like Lead Lag. Let’s simulate filling the tank so the motors cut off. Now let’s lower the fluid to the ON level again, and look – the OTHER motor turned on first this time .. and if we go down to the lag level, this motor turns on. Again, this Duplex mode helps even out the wear on both motors by alternating which motor turns on each time we pass the ON level. One final note: To make sure you have the most recent firmware in your Flowline sensor, just click on Updates. It’s asking if I want to exit without saving my configuration – I do. And then I just click the download button to check for software updates. Mine is up to date, of course, but if it wasn’t you could select that program and update the sensor. Well, that should be enough to get you started. Be sure to check out the other how to videos for more tips on using AutomationDirect’s Products. If you have any questions, you can contact our FREE support via phone, email or the best place to start – the Automation Direct website under the support tab. Also, be sure to check out the Flowline website for more video tutorials and helpful information. And as always, please send us any comments or suggestions you may have – we appreciate the feedback.