Jim Mimlitz, NRI

Navionics Research Inc. is pleased to introduce a MODBUS/TCP and MODBUS/UDP CLIENT feature for its SCADA Server Software system!

Has your Water Utility ever had the need to monitor Office and Plant Infrastructure, such as Power, Generator StatusPhysical Security (Entry & Motion Detection), Office Temperatures, Utility Consumption (Water, Gas, Electricity Meters), and Water Salesmen.  If so, then this new software feature is made for you!

Most often, the SCADA Server is staged at the Water District Office, and the RTU equipment is installed at remote pumping stations, water towers, metering stations, valve stations, etc..

In order to monitor devices at the District Office, an extra RTU could be added to the system.  However, Navionics Research recently developed and introduced an Economical Software Feature that leverages the existing Server computer to co-function as a local MODBUS-over-Ethernet client — thereby obviating the need for an additional RTU and its associated expense.

In a recent project, a client desired to monitor and alarm the Status of a Natural-Gas-Powered Backup Generator and Automatic Transfer Switch at the Water District Office using its SCADA system.  The Water District office has two LANs (Local Area Networks) — one business network and one control network.  A MODBUS I/O device was installed within the Automatic Transfer Switch enclosure and connected to the control  network LAN.

Water District Office, Backup Generator, Automatic Transfer Switch

The following I/O points were desired to be monitored, alarmed, and historically trended:

  • Office Electric Load Transferred and Running on Generator Power (YES/NO)
  • Generator Battery Voltage (Vdc)
  • Generator Accumulated Runtime (Minutes)

The new SCADA software was configured to regularly poll the status of the MODBUS I/O slave using the MODBUS/UDP protocol over the Control LAN.

Automatic Transfer Switch Internals.


Interface Wiring Legend for MODBUS Slave: a) TB1[6,8]-Emergency.Normally.Open b) TB2[3,1]-Battery-Voltage-DC

MODBUS I/O Device. In this application, a SCADAmetrics EtherMeter® was utilized as the Modbus slave device.  The EtherMeter is a versatile Modbus/TCP/UDP device that features 3 digital inputs, 2 analog inputs, 1 battery voltage input, and 2 flow meter inputs.

Due to its I/O Versatility and Rich Industrial Protocol Support, an EM-100 EtherMeter (SCADAmetrics) was Utilized as the MODBUS Client I/O Device.


Another interesting application for this technology was immediately recognized.  In order to satisfy its EPA reporting requirements, a new client desired a system to automatically monitor, alarm, and store historical data from a Water Plant’s Leopold/Xylem Filtration System.  The filtration system’s instrumentation included an Allen Bradley CompactLogix PLC controller and several slave I/O modules.  The filtration system also included one chlorine analyzer and four turbidity analyzers.  Utilized communication protocols included Modbus/UDP, Modbus/TCP, Modbus/RTU, and EtherNet/IP.

This successful project featured SCADA software installation and logic programming that was performed entirely via NRI’s TeamViewer secure remote management console, while the client performed the physical network connection of the filtration system to the Plant’s control LAN (Local Area Network).  Because all NRI setup and commissioning work was performed remotely, the result was substantial cost savings for the customer.

The Leopold/Xylem Filtration CompactLogix Controller’s N-File Mappings were provided to NRI in Excel spreadsheet form, and the customer selected the Tags of interest for realtime display, alarming, historical trending, and EPA reporting.


Leopold/Xylem Filtration Control System: Allen Bradley CompactLogix PLC and I/O Banks.


A Hach SC200 Turbidity Analyzer and Transmitter with Networking Option.


ABOUT MODBUS: One of the key industrial protocols utilized within Navionics Research SCADA Systems, MODBUS has become a de facto standard of industrial communication protocols. It is an especially important protocol when connecting control equipment from an in-homogeneous set of manufacturers. Gathering momentum and support since 1979 when it was first introduced by Modicon (now a division of Schneider Electric), it is the most common means of connecting industrial electronic devices. It is openly published, royalty-free, and forms a relatively easy-to-deploy industrial network.

The new SCADA Server Software with MODBUS/TCP and MODBUS/UDP client drivers is now ready for general deployment.  It is anticipated that its main usefulness will be in Office and Plant Facility Monitoring, such as Power, GeneratorsPhysical Security (Entry & Motion Detection), Office Temperature, Utility Consumption (Water, Gas, Electricity Meters), and Water Salesmen.  If you feel that this upgrade will be of value and benefit to you and the Water District, let me know and we’ll get started.

And as always, if you have any questions, please don’t hesitate to reach out by phone or email.

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