Echelon OpenLNS User Manual

Page 201

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OpenLNS Programmer's Reference

164

a SNVT_xxx type, it will be formatted as specified by the

format file.

2. If the ConfigProperty object’s type does not appear in the

Device Resource File Type and Format files, or if it

appears but is designated as a SNVT_xxx type, the

OpenLNS Server will check to see if it applies to a

standard network variable. If it does, it will be formatted

according to the SNVT format specification in

STANDARD.FMT.

3. As a third option, OpenLNS will use the Hex Byte String

format as the default. In this case, each byte of the raw

value assigned to the ConfigProperty object will be

displayed as two hexadecimal digits. For example, the

byte sequence 1,2,3,4 would be displayed as 01020304.

Overriding the Best-Guess Format
When you successfully write to this property, the new value

will be stored persistently in the OpenLNS database.

However, you can revert the property back to the default

value chosen by OpenLNS at any time by writing an empty

string or the exact name of the type (e.g. SCPTmaxFlow) to

it. There are several possible syntaxes you can use when

writing to this property if you want to override the best-guess

format:
1. A format name beginning with "SCPT" for standard type

formats or "UCPT" for user-defined type formats (e.g.,

"SCPTmaxFlow"). The Data Server will use the resource

file catalog specified using the LdrfCatalogPath property

to search for SCPT and UCPT formats. There may be

several different formats for the same network variable

type. For example, the LonMaker Integration Tool has

two alternate formats for the type SCPTmaxFlow, and

those formats are named SCPTmaxFlow#SI and

SCPTmaxFlow#US.

In OpenLNS, the default formats for types such as

SCPTmaxFlow are determined using the Windows

regional settings of the computer where the data is

formatted (on the computer housing the OpenLNS Server

for local and lightweight clients, or on the computer

running the application for full clients). To determine

the settings being used on a computer, open the Windows

Control Panel and double-click the Regional Options icon.

Select the Numbers tab. OpenLNS uses the value of the

Measurement System field (either U.S. or metric) on this

tab to determine the default format to use for types such

as SCPTmaxFlow. You can also specify a full format

name (e.g. SCPTmaxFlow #SI or SCPTmaxFlow#US) to

select a specific format for that type. For UNVTs, you

must always specify a fully-qualified format name.

2. In some cases, a format exists for a given SCPT or UCPT

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