FAQ

Sounds like you are considering bit banging I2C from the application layer. I recommend using our I2C function. With the I2C function the clock is limited to about 50kHz. The actual maximum will vary between devices and can change with firmware versions. Other concurrent operations such as timers, counters, stream will also affect the maximum speed.

The LabJack U3, U6, and UE9 can function as a bus master, not a slave. The U12 does not have I2C support.

We provide a driver that can be called by VB and VB examples to work from. You can grab the examples here: http://labjack.com/support/ud/examples

Between VB.net and C#.net, our preference would definitely be C#.  We feel like VB is old news and constrained by its origins and find it to be cumbersome and slow.  I have a theory that the main reason VB hangs around is that the "B" stands for "basic" and thus gives the false impression that VB is easier/simpler than other languages.

You have to look at the length of an event.  For events that last less than 1 ms, you need to use hardware to catch them, so that typically means using a timer or counter or stream mode.  For example, connect the switch to a counter which increments an internal hardware register for each falling edge it sees and your software can then read that register whenever convenient.  For longer events, you can consider whether you can poll fast enough even while doing other things, but it depends on the particulars.

For Windows?  A better place for this question would be the U12 Windows Driver Documentation, the U12 Windows Examples, or the LabJack Forum.  I don't know of anyone using the U12 with Scilab, but the place to start would be by looking at the U12 Matlab support.

Also, moving forward, our newer devices (U3/U6/UE9) are more likely to have easy Scilab support.

Yes, we support Python.  Go to our main software page or directly to the LabJackPython page.

The U6 has 4 timers that can monitor 2 quadrature encoders, and has analog & digital I/O, so it does sound like a solution for you.  You might want to give us some information about speed of the inputs and outputs so we can comment on that.

The timestamp is seconds since midnight January 1st (Universal Time), 1904.  See forum topic #9.

There are no speakers or other sound-emitting electronics on the Digit-TL. The alarms (when triggered) will simply produce a different LED behavior when you plug it into a powered USB port.  Furthermore, the alarms are disabled by default, and it is fairly straightforward to turn them on/off within software.

>> use USB<=>RS232 which connecting to the Arduino then it controls
>> digital input of U3 Labjack, is it make any sense?

No, that does not make sense to me.  Software sends some command out RS232, which goes to an Arduino, then the Arduino sets some of its digital outputs, which are connected to digital inputs on the U3, and software reads those digital inputs.  I don't see the point of that.  I suggest posting on our forum to discuss this further if needed.

>> Actually i need 4 DAC, as U3 only provides 2 DAC

Yes, you can use the 2 timers on the U3 to produce PWM output which you filter (providing 0-3.3V DACs), or you could buy an LJTick-DAC.  See Section 2.7.

The UE9 update process will sometimes need to be restarted, but it is very unlikely that the device became bricked or un-recoverable from an update.  Do any LEDs come on when the device receives power?  Can you open a connection to the UE9 using LJControlPanel or LJSelfUpgrade?  Try USB if you were previously using Ethernet, because Ethernet settings will be erased when updating from very old firmware versions.

Also, please read through the troubleshooting options listed on this page. http://labjack.com/support/ue9/users-guide/1.2

On the T7, a name change doesn't take effect until power cycle or reset.  To make it appear changed in Kipling, it stores a local copy of the new name(in addition to writing it to the device) so that users see the new name without a power cycle or reset.  This behavior is to prevent users from changing the name in a loop and breaking flash by exceeding the write endurance.  Rest assured that when you write a new name, the device will remember it, you just can't read the result until after a power cycle or reset.