Welcome to the seventh in our SenixVIEW Video Tutorial series: Pump Control with Alarm.
In this case, we’re going to use the hysteresis band to provide a control band for the pump. We need to make several changes here. The first one is we’re going to assume a 20 inch control range for this particular tank and pump so we’re going to change our set point from 12 inches to 32. And just to make this look a little easier here or clearer, let’s change the max range to 40 inches. Let’s assume our tank doesn’t allow us to go further than that.
Now go to the switch icon and the switch output window. Let’s change hysteresis to 20 inches. In addition, I want to change the polarity of the switch to “On farther”. Okay, then we’ll okay out of that.
Now, the logic of what we have set up is the following: as the level, the sensor is here, remember? As the level drops, we reach the threshold and the pump turns on. The level will rise but it’ll have to go a full 20 inches before it turns off. So that’s the basics of that, let’s copy it to the sensor. And let’s test that and see what happens. So I move my sensor with respect to the computer screen. It comes out farther, watch the transistor symbol on the right. This is way over my shoulder… And it turns on and the pump is on and the level is rising slowly, slowly. We have to get to 12 inches before it’s going to turn off. We’ll continue to come in steadily. We’re approaching it now… And there you are. And as it drops again, it will stay off until it reaches the threshold at 32 inches. It’s on, the level will drop. If we aim at the screen it will be smooth and you’ll see it go off again when we hit 12 inches… And there you are.
Now, let’s consider setting an alarm in the system. We’ll come back and turn on the second switch for that purpose. And we’ll go to the switch output window and in this case, you’ll remember we had switch 2 set in a window mode, so we’re going to go back and put that in set point. And now we want a small hysteresis not a big window so we’ll move that to a quarter of an inch and we can okay out of that. We’ll leave the rest of it the same. Now comes the question: where do we want the set point to be? Suppose your pump, when the level drops, takes a little while to build up. You might set a level — a warning — a low level warning that could be a failsafe to keep you from driving the pump dry if there were no input fluid, for example. Or you might set a switch for overfull to prevent overfilling. Let’s let that happen. And you remember, this window stops at 12 inches, the hysteresis. So let’s just put it at 11 inches for the sake of amusement. We will copy it to the sensor, we got our safety warning, and let’s see how that works in practice. As I move further away from the sensor, the switch turns on. Move toward the screen, we’re in the hysteresis band until we reach 12 inches, which we are approaching… 13, there’s 12 inches. And then we go 1 inch further and you see the alarm switch to turn on to indicate we’ve hit a high level.
So that’s a way of implementing a pump control with alarm. This can be used to control higher current pumps or valves by using the optional relay board that Senix has available.
If you have any questions, please contact Senix customer service. We’re here to help!