NETMF Applications: Remote Cooling Tower monitoring systems with cellular connectivity
A question that I am frequently asked is where has NETMF is used commercially. This would be an easy question to answer if we charged for the platform because we would know who our customers are. But as an Open Source project, we only hear anecdotally what people are doing. I’m starting a series of blogs (NETMF Applications) to share some of these creative implementations with you.
Bryan Fisher III is the owner and principal of Retro-Mation (www.retro-mation.com) in Texas where they offer consulting on complete remote monitoring solutions from system design to field testing. Bryan has consulted on several remote monitoring projects mostly with NETMF for the last five years, for poultry broiler houses, pivot irrigation equipment, denial of service for leased equipment, tank level, and cooling towers. Using computers and sensors for over 30 years, Bryan has been involved with over 100 projects and customers that include energy, civil, mechanical, testing, industrial, and biomedical industries. Bryan has a BSEE degree from TAMU and his career has spanned from mainframes, to minis, to micros and currently NETMF.
One of the areas that Bryan consults in is remote monitoring of water treatment systems which includes water quality and tank levels. He has pre-developed a core piece of hardware to support analog sensors and communications. This device is built on an ARM Cortex M4 processor that runs NETMF using an off the shelf modem to communicate to an IOT portal.
In a recent project, the application required that they be able to detect mineral build up caused by evaporation in the cooling tower. This measurement determines the status of the equipment installed for water treatment. Additional Digital IO is needed to report equipment faults and flow rates. This required adding additional IO, sensors, and associated programming. Cellular communication was required because of the remote location of the tanks but also allows for additional local connections. This device will be able to post events to the portal and to send event messages to service personnel phones. The service personnel can also directly query the devices and change settings like alarm levels over SMS from their phones. Being able to do this reduces the times that the service personnel are required to travel (miles) to the equipment or potentially even to keep staff on site. Settings and phone numbers can also be
configured from a physical port.
In designing the solution several things were considered.
- An off the shelf modem ($100-$200) and a custom NETMF board for small deployments
- A gateway Router ($400-$500) to provide local Ethernet
- A custom NETMF board with a $30 cellular module suitable for larger deployments (this requires additional certification from the carrier)
Given the size of the initial deployment, Retro-Mation went with the first option. The data plans for these devices are about 5 dollars a month easily offset by the personnel cost reductions. An IOT portal from a commercial vendor was selected to be used for daily email reports and data graphing from the hundreds of cooling tower sites maintained by the equipment manufacturer. The various prices quoted from different vendors was from 5 dollars per month to 20 dollars a month depending on level of services and other features
Their software was initially developed on the Netduino Plus 2 while their production board was being built. Using the Netduino specs for their own board avoided having to do a custom port of NETMF. They did change the IO and power circuitry to meet their specific needs. All this allowed the project to be completed in several months. One of the things that stands out in Retro-Mation’s published information is their ability to rapidly respond to needs.
The most challenging aspect of the project was to connect a paddle wheel flow meter to the NETMF device – specifically to enable a DIN for up to 5 events and then disable it and do the math on the interval times to determine flow rate. Bryan’s biggest pain point is the lack of examples in the API reference material for NETMF. What he likes about NETMF is using one IDE to do C# in ASPX, WinForms, Azure, and of course NETMF, just a great debugging platform.
NETMF software will be finished this week except drivers for additional Modems. Boards are being built and will be tested and loaded with software during the first week of Dec. Integration with commercial portal should start at that time with an additional Azure test portal constructed for NETMF hardware validation while the NETMF hardware and commercial portal are being integrated. Factory Testing should start the second week of Dec.
Best of luck on the project Bryan and thanks for sharing your experiences.