System-20 BTU Meter ONICON

The System-20 BTU Meter provides highly accurate thermal energy measurement in water and water/glycol cooling, heating and condenser water systems. Energy measurements are based on signal inputs from a matched pair of temperature sensors and any of ONICON’s flow meters that are ordered separately. The flexible design provides energy, flow and temperature data on the local display via analog and pulse outputs, and over BACnet® MS/TP or MODBUS® RTU networks. Three auxiliary inputs are also provided to totalize pulses from other devices and communicate these totals directly to the network. Chilled water, hot water and condenser water systems for:

• Central plant monitoring
• Campus energy monitoring and cost allocation
• Performance/efficiency evaluations
• Energy monitoring for performance contracts
• AHU and CRAC units for commercial office tenant billing
• Solar, geothermal and ground-source energy monitoring

Features

• Multiple Output
• Simple Installation and Commisioning
• Multiple Flow Meter Options
• Multiple Temperature Sensor Option
• Ideal Submetering Solution
• Built-In Interval Data Logger
• User-friendly Interface

Specification

Liquid Flow Rate	See accuracy statement provided with the flow meter (ordered separetly)
Differential Temperature	Meets EN1434/C900.1 accuracy requirement for 3K sensors
	Available Options	-Precision solid state current based sensor. Signal (mA) is unafected by wire length. Overall differential temperature measurement uncertainty of ±0.15ºF over the application range. - 1000Ω platinum RTDs calibrated to a differential measurement uncertainty of ±0.18ºF over the stated range
Calculator	Meets EN1434 Class 1 requirements with 3K minimum Δt
	Computation Error	≤0.09% at 30°F Δt
Mechanical	Dimension	5.5" H x 6.5" W x 4.25" D
Material	Enclosure	Glass filled polycarbonate with a UL-94 flammability rating suitable for use in pleum spaces
Enviromental	Meet EN1434/C900.1 Class B requirements
	Operating Temperature Range	-13ºF to 140ºF
	Enclosure Rating	NEMA 12K
Power Supply Requirements	20 - 28 AC/DC, 50/60 Hz 500mA DC or 1A AC maximum input current
Isolated Analog Output	May be programmed for energy rate, flow rate, supply temperature, return temperature or Δt
	Configurable	4-20 mA, 0-5V or 0-10V output
Isolated Totalizing Solid State Contact Closure Pulse Outputs	May be programmed for energy, volume, alarm indication, mode indication or MODBUS coil indication
	Contact Rating	50 mA, 30 V
	Contact Pulse Duration	50, 100, 500 or 1000 ms
Isolated Totalizing Pulse Input	For use with devices providing sinking open collector or dry contact ouputs
Network Connection	Isolated RS485 serial interface
Communication Protocols	Available Options	- BACnet MS/TP per ASHRAE standard 135.1: 2009 - MODBUS RTU
Network Configuration & Addressing	Baud Rates	4800, 9600, 19200, 38400, 76800, or 115200
	Device Address Range	1 – 127 (1 - 247 MODBUS® RTU)
	Device Instance Range	None, Even, Odd (MODBUS® RTU only)
	Parity	None, Even, Odd (MODBUS® RTU only)
Approval	FCC	Part 15, Subpart B
	BTL	Certified to ASHRAE 135:2009
	UL Listed
	CE