Jim Mimlitz

Jim Mimlitz, SCADAmetrics

The Neptune Tru-Flo Compound is a very popular water meter used in applications where there is a high degree of anticipated variance between the maximum and minimum rates-of-flow. The meter features two internal meters: a high-flow meter to measure faster flow rates, and a low-flow meter to measure slower flow rates. Each meter is coupled to a dedicated register that displays and transmits its total consumption reading.

Neptune Tru-Flo Compound Water Meter.

Traditionally, co-metering of the Tru-Flo between the utility’s AMR system and a SCADA system made use of Neptune Tricon/E3 pulse (or milliamp) adapters installed between the meter and the two registers. Basically, the utility used the encoder signals, and the SCADA system used the pulse (or milliamp) signals.

However, it is noteworthy that the pulse (or milliamp) signals from the Tricon/E3 do not convey the meter’s totalizer reading, and therefore place a burden upon the SCADA system to count pulses. Speaking from experience, the SCADA system totalizer will generally drift apart from the flow meter’s totalizer reading, rendering it unusable for most EPA reporting purposes.

In order for both the utility’s AMR system and the SCADA system to split and share the encoder signals, SCADAmetrics’ Model SDA’s (AMI Duplexer for SCADA Systems, Din-Rail Version) are deployed.

Model SDA, “AMI Duplexer, SCADA-Version”

A Co-Metering package for the Tru-Flow compound, based upon SDA “SCADA Duplexers” and an EtherMeter, is illustrated in the figure below. Note that the interface to the SCADA system is via a single Ethernet cable, through which both totalizer and rate-of-flow information is digitally conveyed. The communication protocol can be either industry-standard Modbus or industry-standard Rockwell EtherNet/IP. This system leverages Neptune’s absolute-encoder technology (E-Coder or Pro-Coder register) to ensure that the SCADA system’s totalizer readings are an exact match to the two register’s readings. The EtherMeter also supports Modbus/RTU and DF1 for SCADA systems that prefer a serial data link.

Wiring Diagram – EtherMeter, SCADA Duplexers, Neptune Tru-Flow Compound Meter. (Click to Zoom.)

Are you interested in how SCADAmetrics technology can help connect your Tru-Flo compound meter to your SCADA, Telemetry, or Building Automation System? Give us a call! We’ll be glad to discuss the details!

Jim Mimlitz

About Jim Mimlitz

Licensed Professional Electrical Engineer @ SCADAmetrics. Specialties: Connecting Flow Meters with SCADA, Telemetry, and Building Automation Systems. Electronic Circuit Design, Software Development.

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