Digital Flowmeters: Converting Them to Serial Communication

Model 9090-DAT

An international customer purchased three Digital Flowmeters, model 9090-DAT in yr2018.  This model number refers to the EXAIR Rev3 Digital Flowmeter with a Datalogger (photo above) for ½” Schedule 40 black pipe.  They used the Datalogger to log flowrates for their blow-molding machines.  A new engineering manager joined their team and was looking for a more “real time” reading of the flowrates.  They could compare flow data results from prior setups to monitor the program for their current blow-molded products with certain materials and sizes.  It was important for quality control to measure and compare the results to verify the proper machine set points.  They contacted EXAIR to see what we could offer.

EXAIR offers a variety of Digital Flowmeters for black pipe, aluminum tubes, and copper pipes.  They can accurately measure compressed air and nitrogen flow by measuring the temperature difference between the two probes.  The display is large for easy reading, and it can be programed for different units like SCFM, M3/hr, and M3/min.  For software data collection, we have the Wireless communication, USB Datalogger, and wire communication.  We also have Hot Tap versions, Pressure measuring, and Remote Display. 

In describing their current programming system, they were using a Modbus RS485 network.  This type of network system uses a “master” device to communicate with multiple “slave” devices.  In this instance, they were going to use a computer as the “master” device to communicate with the Digital Flowmeters.  With this type of serial communication, each Digital Flowmeter would have a particular and exclusive node address.  The master device can “open” the serial communication with that particular Digital Flowmeter and transfer data points of flow measurements.  The serial boards that EXAIR uses can connect to over 100 meters with a total length of 4,000 feet (1,212 meters).

Now, for our customer above, they did not need to purchase different Digital Flowmeters.  EXAIR offers a model 901785 serial communication board to convert the standard Rev3 Digital Flowmeter to connect to Modbus RS485.  They purchased three of them and converted each unit that they had without removing them from the compressed air system.  Since they were using the serial communication to connect to a computer, they requested an Ethernet connection.  EXAIR is able to convert serial communication to either Ethernet or USB connection with a converter.  With the Ethernet converter, they were able to connect directly to their computer.  They downloaded a software program at no charge to start monitoring and collecting flow information from all the digital flowmeters.  This improved the setup times for each machine.  As an extra bonus, they could also determine if they had some pneumatic issues with valves, cylinders, or leaks with the readings from the Digital Flowmeters. 

EXAIR Digital Flowmeters for large pipe

When you need to analyze your pneumatic components, flow is an important point.  The EXAIR Digital Flowmeter can give you that important data point.  You can cut energy consumption, improve pneumatic efficiencies, reduce setup times, and save yourself money.  If you are missing that detail with your pneumatic system, an Application Engineer at EXAIR can help you select the best Digital Flowmeter.  And if in the future you wish to upgrade, we may have a simple solution for you as seen with our international customer above. 

John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb

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