The Contrec Model 515 (Application FA03) is an add/subtract flow computer for energy measurement, built to take two independent flow inputs and either add them together or subtract one from the other to give a combined or net result. It’s the energy-metering version of the standard 515 add/subtract application, so it’s normally used on thermal energy loops where you need a running total across two flow paths, not just a single meter reading.
The two input channels accept a wide range of frequency signals (millivolt, reed switch, Namur proximity, open collector) or scaled analogue signals, so it can take a re-transmitted signal from another field flow computer on one channel and a raw pulse or millivolt signal from a flowmeter on the other, if that’s how your setup is wired.
In actual application, this application code is normally paired with two flow measurement points feeding into one energy total – for example a supply and return, or two parallel lines. The 515 has an onboard adjustable transducer excitation supply so you can power the field sensors directly, plus freely assignable high and low alarms, 4-20mA retransmission, and dual RS-232/RS-485 Modbus RTU ports so it reports into your existing SCADA or DCS setup.
Before we quote this, we would normally check the signal type on each channel (frequency or analogue), whether you need addition or subtraction between the two, and what alarm and output signals your control system needs. Hope this helps.
