Getting started with Amphenol Advanced Sensor's NPI-EVAL-Kit and Nova I2C Pressure Sensors

Automation and Control Sensors Transducers
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Description

Amphenol Advanced Sensors’ NPI-EVAL-KIT allows quick evaluation of their NPI-19 Nova Sensor series of digital I2C industrial pressure sensors. This post will discuss contents of the kit, setting up the kit hardware and software, and using the kit with an example NPI-19 series I2C pressure sensor.

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Hardware

  • NPI-EVAL-KIT
    Nova Sensor NPI-19-I2C Evaluation Kit
  • NPI-19M-002G2
    Nova Sensor NPI-19M Industrial Digital I2C Pressure Sensor, 2.5psi Operating Pressure

Software

  • NPI19_EVT
    MATLAB Runtime and NPI19_EVT executable GUI software (included with NPI-EVAL-KIT).

Background

Amphenol Advanced Sensors NPI-19M series of digital pressure sensors is offered in a broad selection of options including thread versions, pressure ranges and absolute and gauge pressure types as shown in chart below.
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Setting up the kit for evaluation of a Nova Sensor NPI-19M I2C Pressure Sensor

1 - Kit contents consist of an evaluation board and USB drive. The evaluation board includes a USB interface, power input, I2C sensor interface connector, OLED display and on/off switch. The kit provides the ability to display sensor data on either the board’s OLED display or PC GUI and ability to data log sensor data to a file on the PC.
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The USB drive contains three files, including an application note, user guide and evaluation software installer.

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(note: not included in the kit but needed for operation of the evaluation kit are a NPI-19 sensor, USB cable and power supply)

2 - The eval kit software consists of the NPA19_EVT MathWorks runtime application that runs on a Windows PC. The application GUI provides the capability to start/stop/save the sensor data and toggle the OLED display on/off

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Detailed instructions on installing and using the software can be found in the NPI-19-I2C evaluation Kit User Guide.

3 - Make note of the correct I2C connector/cable orientation and plug in a NPI-19M sensor (for this example, a NPI-19M-002G2 was used for testing purposes). You will also need a power supply with output voltage of 2.9V to 5.5V. Connect a USB cable to the PC running the NPA19_EVT evaluation software.

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Start the NPA19_EVT software and select the COM port for the evaluation board. Once connected, sensor data can be displayed on either the OLED or application GUI. Additionally, the NPA19_EVT software can be configured for sampling rate and data logging the sensor data to a .csv file.

Conclusion

Amphenol Advanced Sensors’ NPI-EVAL-KIT provides a quick and easy method to test and evaluate their broad offering of NPI-19M series of digital industrial pressure sensors. The kit provides flexibility for testing the sensors with various sampling rates and power supply voltages.

References

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Absolutely wonderful thank you. Syetems onboard are currently useing a discontinued Honeywell brand I am currently looking for a viable replacement for. Seems the newer brands dont have quite the physical traits to hold onto the tubing.

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Thank you so much, @ScottRaeker, for this post. I did not purchase the eval board, but the NPI-19J I2C discrete sensor. The Nova documentation I could find does not give the pinout of the ribbon cable! And it is practically impossible to get in touch with anyone at A-S Nova to get that answered. But it’s in the eval board documentation that you shared. Thank you!

I am connecting this to a BeagleBone Black via I2C. We read many other sensors over I2C so I sure hope we can get this one going. We write in C so if you have any tips for doing that, please share them!

In addition, Nova does not explain how this device should be mounted at all. The port screws into a 18" NPT fitting on the fluid system, but how is the sensor supposed to be mounted in an enclosure? There’s nothing on that. We are putting it in an IP66 enclosure, drilling the enclosure so the port protrudes, putting a rubber gasket/washer on, and then using a 1/8" NPT low-pressure chrome-plated brass pipe fitting (McMaster-Carr) to tighten it in the box.

Fingers crossed that this works.

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@walterc

The below link for the NPI-19J on page 2. The cable pinouts are listed

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As for mounting this to / in an enclosure and also connecting it to a fluid system.
I would think that the solution you outline would probably work too.

As for the coding. @Matt_Mielke / @rick_1976 any insight that we would be able to provide?

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@Nathan_2268 Thanks! I have that page in the documentation and it gives me what I need to size an enclosure. It’s just that there isn’t anything that explains how to secure the device to the box once it is pushed through the hole in the box. I’ll try to share how our approach works.

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Coding would be similar to other I2C devices; start with a standard library, configure per datasheet specs, speak the Special Words while going between the datasheet, 'scope, and degugging environment trying to figure out why it didn’t work last time, rinse/repeat until success… It appears that the transfer function is somewhat awkward however, so a calibration routine of some sort would seem likely.

Regarding mounting, the form factor of the product would seem to anticipate use entirely within an end-product envelope, rather than traversing it As described, it would seem that the application is measuring the pressure of its ambient environment, which seems a less-common scenario for which other products may be available, but that would be a discussion for a separate thread.

Use of an elastomeric gasket and an NPT nut of the sort referenced might get a person to a workable state in the latter case, but seeing as NPT threads are tapered to allow formation of a fluid-tight joint I’d anticipate a lot of interplay between gasket and wall thickness, assembly torque, tolerances among all those and perhaps a few other factors in terms of the assembly’s sealing, vibration tolerance, and other performance factors.

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@rick_1976 Thanks for your thoughts on this.

there isn’t much in the data sheet ablut mounting it for any application. Let’s forget our application. Do you know how it would be mounted in an anticipated application?

We are measuring the pressure in a 1/2” prater pipe as part of a process. There are many other sensors that can do this but not at this price point. Our application is on a mobile autonomous system too.

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A typical application would see the sensor’s thread screwed into a corresponding 1/8" NPT female thread tapped or fitted to the pressurized region.

First example that comes to mind might be a battery-powered tire inflator with digital readout. Such a device may plumb such a sensor internally via a tee fitting between compressor and output.

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@rick_1976 Yes, that his basically how we are connecting the device to the media. We have a brass tee in line on the water line. We will screw the 1/8" NPT threads of the sensor into that tee. The problem is how to protect the electronics (the other end) of the sensor. I would expect that side to also have some threads that would allow us to tighten the device to the wall of an IPxx enclosure. One of the diagrams indicates “TIG weld.” I don’t have experience with these but it would seem that TIG welding these in place would be hard to do without damaging the electronics board on the back side of the sensor!

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In the inflator example, the sensor with its related electronics would be contained entirely within the end-product envelope, providing the necessary degree of protection. The form factor is largely geared toward that sort of application as an internal component, whereas your application would seem to involve some portion of the sensor residing in an exposed environment.

Be advised that there are separate “regular” and “industrial” pressure sensor families to look at, the latter of which may have products of a form more suited to the need. As for the “weld” annotation, that’s likely indicating the location of a factory weld made during the manufacturing process.

Some images of the intended application may help facilitate dialog on the topic. Feel free to send via private message (click user avatar, then “message”) if you’d prefer a degree of discretion in the matter.

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@rick_1976 Thanks. Once I have this a bit more put together I’ll take a photo and PM it to you. I appreciate your offer. Re: regular and industrial, I’m not arguing with you at all about that. However, when I searched DigiKey for a sensor for this application, the NPI series came up under “Industrial Automation” So, I guess I assumed it would fit our application with the appropriate enclosure. Shame on me for not digging into the mounting more however, I do think I can make it work. Time and testing will tell.

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To close this out, here are some photos of how I assembled this. It works very well with no leaks.
The box is an ABS plastic IP68 enclosure.
The nut on the outside is from McMaster-Carr, their part number 9162K181

We used a brass NPT to hose barb connector from the local hardware store to connect the rubber hose.

So far, this has all handled up to 92psi. Our design range is 80-85psi so we expect all to be good!

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Thanks to all for your suggestions and help!
I was making this much harder because I was going back to my power plant control systems work as an engineering student and trying to mount the sensor directly to the rigid pipe. The rubber hose approach makes this much easier!

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