Onicon System-10 BTU Meter User Manual

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System-10-LON Network Interface Installation Guide 07/13 - 0654-4 / 16751 Page A-3
INTEGER FORMAT OUTPUT NETWORK VARIABLES
Integer format output variables are limited to 2 bytes of data. For this reason, the maximum number that
can be transmitted in this format is 65,535. Values for both rate and total data from the Btu meter will often
exceed this limit. For this reason, energy rate data is scaled and energy totals are transmitted in segments
using multiple variables. This is explained in detail below.
Volume and Energy Rate Variables
The integer output network variables for volume and energy rate are described in the table below. Column
1 contains a brief description of the network variables. Column 2 contains the network variable names.
Column 3 contains the Lon SNVTs used for each variable. Column 4 contains the engineering units and
column 5, the valid range for each variable. Please note that while the oating point variable for energy
rate is transmitted in Watts, the integer network variable is transmitted in kW to ensure that the maximum
rate never exceeds the register capacity.
Integer Output Network Variables
Description Variable Name SNVT Name Engineering Units Valid Range
Flow (volume) rate nvoVolRateLi SNVT_ow Liters/Sec 0 to 65535
Mode status indicator nvoModeStatus SNVT_char_ascii
Supply temperature nvoSupplyTempi SNVT_temp_p ° C -17.778 to 260.0
Return temperature nvoReturnTempi SNVT_temp_p ° C -17.778 to 260.0
Delta temperature nvoDeltaTempi SNVT_temp_diff_p ° C -327.68 to 327.66
Energy rate nvoEnrRateKWi SNVT_power_kilo KWatts 0 to 65535
Volume and Energy Total Variables
The integer output network variables for volume and energy total are described in the table below. Column
1 contains a brief description of the network variables. Column 2 contains the network variable names.
Column 3 contains the Lon SNVTs used for each variable. Column 4 contains the engineering units and
column 5, the valid range for each variable.
Please note that while the oating point variable for volume total is transmitted in liters, the integer
network variable for volume total is transmitted in kLiters. This is done to increase the maximum total
that can be transmitted via the integer variable. Total(s) must be reset before the accumulated value
exceeds 6553.5 kliters using nviResetVol1a and/or nviResetVol2a. If this is not done, nvoVol1KLi and/or
nvoVol2KLi will over range and continue to indicate 6,553.5 kliters (1,731,252 gallons) until the
System-10’s internal total rolls over to zero.
A separate integer SNVT is also available to transmit ow totals in liters. This variable is only used in
special small pipe applications as the maximum total it can accumulate is only 65,535 liters (17,312
gallons) before it must be reset.
Energy totals are handled in a slightly different way. The oating point variable for energy total is
transmitted in Btu but the integer network variable for energy total is MBtu. This total will over range at
65,535 MBtu. The internal total stored in the Btu meter will not roll over until it exceeds 99,999.99 MBtu.

Onicon System-10 BTU Meter Specifications

General

Brand	Onicon
Model	System-10 BTU Meter
Category	Measuring Instruments
Language	English

Summary

SECTION 1: INTRODUCTION

Purpose of This Guide

This guide outlines the installation, commissioning, and servicing of the ONICON System-10 BTU Meter.

Typical System-10 BTU Meter

Explains the ONICON System-10 BTU Meter's function as a heat computer using sensor data for measurements.

Specifications

Details the technical specifications for the ONICON System-10 BTU Meter's Lon Talk network interface.

NETWORK SIGNAL CONNECTIONS

Lon Talk Connection

Describes the 2-wire serial output connections for Lon Talk to terminal T1, including torque specifications.

Optional Pulse Input (Di3)

Covers configuration of the auxiliary pulse input for totalizing outputs from external devices like water or gas meters.

NETWORK ADDRESSING

LonWorks Network Addressing

Explains the unique 48-bit Neuron ID used as the Node ID, combined with Domain/Subnet IDs for device addressing.

COMMISSIONING THE SYSTEM-10-LON

Service Pin LED States

Details the meaning of the yellow service pin LED states for Lon Talk network connection status.

LONWORKS XIF FILES

Output Network Variables

Describes how the System-10-LON transmits data via SNVTs, including floating point and ASCII formats.

Integer Format Output Variables

Explains the use of integer format output variables for systems that cannot accept floating point data.

Input Network Variables

Details input network variables used for remote commands to reset totals, utilizing ASCII format.

Node Object nviRequest

Details the five input variable requests implemented for the node object, including mandatory functions.

Node Object nvoStatus

Describes the six status object functions that report status information to the network.

Resetting Totals via Network

Explains methods for remotely resetting flow, energy, and auxiliary input totals using input variables or nviRequest.

Rollover of Totals

Details how flow and energy totals roll over to zero when the maximum count is exceeded.

NETWORK TROUBLESHOOTING TIPS

Troubleshooting Common Issues

Provides solutions for common reported problems like no flow signal, incorrect flow rate, temperature issues, and communication errors.