The latest post from NI News promotes the use of the quick drop feature in LabVIEW. I’m not a big user of quick drop since I loathe switching between two-handed typing and one-handed typing/mousing positions (and yes I realize I could set up one-handed short-cuts, but I’m really not that fast anyway). There is one use, however, that I find invaluable when working on projects that include dozens or hundreds (or thousands) of VIs. The quick drop search includes more than just what’s in vi.lib, VIs that are included in your project explicitly as well as those that appear as a dependency are returned as well. This significantly reduces the amount of time I spend searching through the project for a specific type def or FGV call. And now you know!
I’m excited to announce that I’ll be teaching ELEC 460/860 (LabVIEW Programming) at the University of Nebraska in the fall term of 2014. It’s been a while since I last taught in a university setting, but I’m eager to work with engineering students again.
Maybe this has happened to you: you’ve created several LabVIEW classes, monkeyed around with the class properties (inheritance, perhaps), and then, seemingly out of nowhere, one of your classes is now locked. LabVIEW will claim:
The library is locked for the following reason(s): This LabVIEW class is loaded in multiple application instances. Classes must be in only a single application instance to be edited.
Nonsense. You’ve never used this class anywhere else! Before you start wondering if you suffer from multiple personality disorder, try this little trick:
- Open up the relevant LabVIEW project and navigate to the class in question. Notice the key icon beside the class name.
- In Windows Explorer, navigate to the offending .lvclass file.
- Open the .lvclass file.
- Save everything.
- Notice how the key went away? Good.
I’m almost embarrassed to share this, but after some fruitless googling I decided it’s useful enough that it needs to be out there. So… here you go: apparently you can copy an object (or group of objects) from a LabVIEW front panel or block diagram and paste them as an image in another application. Who knew?
Two nights ago my furnace began short cycling. Short cycling is when the furnace will kick on for a few seconds, then shut off for a few seconds, then back on, then back off, repeat indefinitely. It’s loud and it doesn’t heat anything. For me, the timing couldn’t have been worse: a polar vortex slipped down that afternoon bringing with it the coldest temperatures we’ve had in decades. I ended up tinkering, but couldn’t make any progress. I moved the kiddos into the one room in the house with baseboard heating, and called a service technician in the morning. With his help and the help of Nest phone support I was able to get everything back up and running. I couldn’t find this solution online anywhere, so I’ve posted it here hoping it’ll save someone else a frigid night.
I’m not a heating and cooling expert, so I’ll only claim this solution is helpful for my system as configured. It’s a common configuration, but if yours differs, you may have to do a little more digging. My HVAC setup:
- Furnace (forced air)
- Air Conditioner
- Nest 2
I have four wires connected to my Nest:
- Yellow (Y1), AC
- Green (G), Fan
- Red (Rc), Power to switch
- White (W1), Heat
The technician was able to narrow down the problem to my Nest thermostat. The quickest way to eliminate the furnace as the problem is to:
- Turn power off to your furnace.
- Remove the Nest thermostat from your wall.
- Remove the Red (Rc or Rh) and White (W1) from the thermostat.
- Connect the Red and White wires together (twisting, alligator clips, or whatever you’ve got to move those electrons).
- Turn power back on to your furnace.
A thermostat is basically a programmable switch. When your heat comes on the thermostat switches power to the white wire from the red wire. That’s why this should work. If your heat comes on after shorting the red and white wires together and is no long short cycling, your thermostat is likely the problem.
Here’s how to fix your Nest thermostat:
- Turn power off to your furnace.
- Remove the Nest from the wall (if you haven’t already).
- Replace the red and white wires to their original locations (if you haven’t already).
- Remove the Yellow (Y1) wire and tuck it away safely.
- Put the Nest back on your wall.
- Turn power back on to your furnace.
So what’s happening? Honestly, I’m not entirely sure. The explanation I got from Nest phone support was that the extreme cold was affecting the yellow wire that runs outside to the air conditioner somehow. Sure. I’ve seen others complain about battery problems and software updates, so take it for what it’s worth. Regardless, removing the yellow wire solved my short cycling problems.
This is only a temporary solution for when it’s insanely cold. Once the polar vortex leaves and temperatures return closer to something resembling normal, I’ll reconnect the yellow wire. Otherwise the AC won’t turn on once temperatures really get up there.
If you haven’t heard yet, Alfred 2 is out. The new version introduces workflows to the Powerpack, which I’m quickly finding to be indispensable. I’ve created a workflow for adding a single to-do or a to-do list to Evernote. It works by typing “todo” then the text you want to follow a checkbox. You can also append tags with a “#” (each tag gets one, this allows for tags with spaces). To create a to-do list, type “todos” followed by the list title (optional) then mark off each to-do with a “*”. Tags work here as well.
If you’re not already using checkboxes in Evernote, you’re doing it wrong. They’re searchable, so as you’re taking notes just drop in checkboxes next to your actionable items. Later you can search for unchecked checkboxes to build your to-do list. If you’re big on the GTD approach (as I am) you can include tags for context (i.e. at work, at home, calls, etc.). There will be more from me re: Evernote and GTD, so stay tuned.
With the recent release of iOS 6.1 and the evasi0n jailbreak, I was tempted to re-jailbreak my ancient iPhone 4. iOS has come a long way since that phone’s debut, so most of my hang-ups have been dealt with. There is one glaring feature missing that ought to be standard: WiFi hotspot. This has been less important to me since my switch from field work to mostly development. Recently, however, I’ve found myself on-site and unable to get to a much needed repo update. So jailbreak it is.
However, I was concerned about my recent investment in the iOS Developer Program and whether I’d still be able to run and debug my code on my iPhone. Two minutes of searching didn’t really reveal what I needed so I went ahead and did the jailbreak anyway. And yes, as I’m sure as you’ve guess from the title of this post, I am able to run and debug my apps to my jailbroken iPhone with no issue. And now you know.
This is a real quick one that I wish I had figured out a lot faster earlier today: apparently a NaN from LabVIEW can’t go into a MySQL double. You need to check for NaN before writing to your database. Be especially mindful of this if you’re doing any type of counter measurement with NI equipment since they’ll return NaN when no pulses are detected on a timeout. That is all.