LJStreamUD

LJStreamUD.exe, V1.09, Aug 30, 2010

Ready-to-run executable streams analog inputs from 1-16 channels on a U3, U6, or UE9. Displays selected channels on a graph and writes data to file. Executable requires the LabVIEW 6.0 run time engine (which can coexist with other versions of the LVRTE). The LVRTE6 is installed by the U12 Legacy software installation, can be downloaded here, or can be downloaded at ni.com.  Get the LJStreamUD executable at the bottom of this page, or for LabVIEW programmers the source code is available in the LabVIEW_LJUD archive.

See Section 3.2 of the applicable user's guide for background on streaming. Also see the analog input section (2.x) and the UD driver stream section (4.3.x).

It is recommend to initially just open and click "Start Stream" without changing any settings. If you have already changed some settings and are having problems getting it to run, close the program and delete "ljstreamud.cfg", then open again and you will have the default settings.

LJLogUD vs. LJStreamUD: LJLogUD uses command/response mode as documented in Section 3.1 of any UD series user's guide.  It acquires and processes 1 scan at a time at the specified Interval.  Generally used for perhaps 10 scans/second or slower.  LJStreamUD uses stream mode as documented in Section 3.2 of any UD series user's guide.  Each iteration it retrieves and processes 1 seconds worth of scans.  Generally needed for perhaps 100 scans/second or faster.

# Channels: 1-16.

Scan Rate: Put in the desired scan rate.  Sample rate is scan rate times # channels.  See Section 3.2 of the U3/U6/UE9 User's Guide for more information.

SettlingFactor: 0-255.  See Section 5.2.12.

+Ch/-Ch: Put in the desired positive and negative channel numbers.

Ranges: Select the desired range, which is related to gain.  Not all devices support all ranges, but starting with UD V3.19 the driver will select the best range available rather than throwing an error.  For more information, see the AIN section in Section 2 of the U3/U6/UE9 User's Guide, and also see Section 4.3.3 of the applicable user's guide.  The U3 does not have normal range options, but does have the "Special" range which is enabled by setting the negative channel to 32.

Write To File: Click this to start and stop writing to file.  The resulting file is a tab-delimited ASCII file.  Files are written with a .dat extension.  To quickly open in Excel or Open Office Calc, change the extension to .xls or .ods.

Data File Prefix:  LJStreamUD uses this as the base string when it makes a file name.  When LJStreamUD starts a new file, it appends a "_#" to the specified prefix, where "#" is an unused number from 0-99999.

Max File Size (Bytes):  When the current data file exceeds this limit, it is closed and a new file is started.

Graph History: Controls how many scans are shown on the graph.

DisableScaling:  Scaling is computing intensive.  If UD Backlog is growing, disable scaling.

Scaling Equations: Should be something like "y=a", where "y" is the scaled output and "a" is the input voltage of the 1st channel.  "b" through "p" would be the input voltage of the rest of the channels.  Common examples:

y=c
y=c+273.15                         //deg C to deg K
y=100*c                              //EI-1034 voltage to deg F
y=0.5556*c - 17.78              //EI-1034 voltage to deg C
y=0.5556*(c-32)                  //EI-1034 voltage to deg C
y=c^2                                 //c*c or c-squared
y=c-273.15                          //deg K to deg C
y=((c-273.15)*9/5)+32        //deg K to deg F
y=(1.8*c)-459.67                //deg K to deg F rearranged

There is special support for the thermocouple function from the UD driver.  The form is "TCVoltsToTemp[type:volts:CJtempK]".  Type should be B, E, J, K, N, R, S, or T (must be capital).  Volts is the thermocouple voltage, and can be a formula.  CJtempK is the cold junction temperature in degrees K, and can be a formula.

y=TCVoltsToTemp[K:c:298.15]
y=TCVoltsToTemp[K:c:d]
y=TCVoltsToTemp[K:c:55.56*d+255.37]
y=TCVoltsToTemp[K:c-0.0002:d]
y=2*TCVoltsToTemp[K:c:d] - 2.5

Revision History:

1.06: Not compatible with older config files, so delete ljstreamud.cfg before running the first time!  Changed config file delimiter to "#!#" instead of "," for better international compatibility.  Made maximum file size a user control.  Scaled values now grayed-out if scaling is disabled.

1.07: Turned on scroll bars, for use on smaller monitors.

1.08:  Minor changes to the process used to find the next available file number.

1.09:  No longer disables timers and counters.  Added controls for Resolution and SettlingFactor.

File attachment: 

LJStreamUD_build.zip