- BTU
- Signal conversion to Lonworks® networks
General information
The series 340 LW BTU transmitter is an economical, compact device for submetering applications that communicate via a Lonworks® network.
The 340 LW calculates thermal energy using the signal from a flow sensor installed in the systems inlet and outlet points. The flow input may be provided by a sensor and many other pulse or sine wave signal flow sensors. The onboard microcontroller and digital circuitry make precise measurements and produce accurate drift free outputs.
The 340 LW is commissioned using Windows® based software. Calibration information for the flow sensor, type and pipe size may be preselected or entered in the field. While the unit is connected to a PC or laptop computer, realtime flow rate and total, temperatures and energy rate and total are available.
Measuring principle
Impeller meters

The series feature a six-bladed impeller design with a proprietary, non-magnetic sensing mechanism. The impeller shape coupled with the absence of magnetic drag provides accuracy and repeatability throughout the flow range of the sensors. As the liquid flow turns the impeller, a low impedance square wave signal is transmitted with a frequency proportional to the flow rate.