What is Modbus? And why does APG use it?

Encoders on a coilThere are so many communications standards out there: Modbus, Fieldbus, Profibus, Hart, and that’s just a few. You can get systems with HMI’s and PLC’s and RTU’s and… Yikes!

So how do you choose? What do they mean? “I just want to get the readings from my sensors!”

We hear you. We make several of our sensors Modbus-compatible, but we don’t do it for our sake, or even Modbus’s sake. We do it for you. So today, let’s take a look at what Modbus is, and why we use it.

Liquid Level Sensor Technology Decision Tree

illuminated exclamation mark in a field of dark question marksHere it is, the week after Christmas, and you still haven’t gotten that special something for your process system. A liquid level sensor would be great, but you just aren’t sure what type of sensor would be best for you, uh, your process system.

Well, APG is here to help. No, we didn’t put together a comprehensive gift guide for your process system. But, we did manage to assemble this handy-dandy Liquid Level Sensor Technology Decision Tree. Answering each of these questions will help you identify the liquid level sensor technology that best fits the needs of your system.

Changing Response Times

Emergency LightTiming is everything for your sensors. A sensor that is too sluggish to respond to quickly changing levels or pressure won’t alert you to dangerous process conditions until it’s too late. And an overly sensitive sensor sees an emergency in every stray reading or transient condition. Neither sensor is effective, in terms of time or money.

Sensors using sample buffers for signal processing can condition Output Readings using various combinations of four settings: Sample Rate, Averaging, Window, and Out of Range Samples. All four work together to produce an Output Reading customized to your liking. Let’s take a look at them individually, and then look at an admittedly staged example to see their cumulative efforts.