Comments on: LabVIEW tip: easy relative timestamp calculations

By: Jim Kring

Jim Kring — Tue, 12 Jun 2007 17:10:43 +0000

Yes, units are one of those tricky features in LabVIEW that presents some issues for others who will inherit your code and have to decipher your intent. Generally, I don’t use units on subVI inputs. Also, I always add a comment to my code that describes what I did and why (e.g., to call out that 1 d means 1 day and not one second).

By: Alvin Moore

Alvin Moore — Mon, 11 Jun 2007 13:59:35 +0000

Great tip, Jim. One thing I noticed in trying it is that you need to be careful if you use this on a subvi input. I built a sub with an input with the units set to minutes, thinking that if I now use this sub, the input there will be minutes. However, when I dropped this sub on a diagram and created a constant, the constant had units too, and the default was “s”, so instead of adding 5 min I was only adding 5s. I had to manually set the units on the constant to input 5 minutes into this control. I can see how this behavior could be argued either way. It seems to me the constant should be forced to adapt to the control units values, because that is set on the input of the sub, but that is not the case, so it is wise to be careful in use of this ability in subs.

By: Yen

Yen — Sat, 09 Jun 2007 18:27:54 +0000

Correction: it does work in 7.1. I just forgot to change the constant value from 0.

By: Yen

Yen — Sat, 09 Jun 2007 18:27:06 +0000

When did this start?

I know it does not work in 7.1.

By: Ed

Ed — Fri, 08 Jun 2007 18:06:36 +0000

That’s one of those, “Why didn’t I think of that!” moments.

Thanks for the tip Jim.

By: Altenbach

Altenbach — Fri, 08 Jun 2007 17:37:18 +0000

Another useful time unit are SI variations such as e.g. “ms”. Obviously works equally well.

Try to add 1000ma and you’ll move up one year. Silly!

By: Ben

Ben — Fri, 08 Jun 2007 17:29:57 +0000

Using 1 year does not seem to work correctly.

It looks like we have a leap year coming up but that does not explain what I am seeing with the rest of the time.

Ben

By: Ben

Ben — Fri, 08 Jun 2007 16:25:05 +0000

I’ll have to try this out myself.

If the unit is years, does leapyears come into play?

Similar to the note about not doing a “transpose” on a graph because it could be missed by readers, there is a danger of people who do not know this tidbit, could freak-out when they first it.

Thank you for sharing Jim!

Ben

By: Jim Kring

Jim Kring — Fri, 08 Jun 2007 15:38:42 +0000

Carsten: Yes, setting the unitless floating point to a display mode of HH:MM:SS is another great tip!

Ton: I think that I learned this by just trying it. I thought to myself, “it would be great if I could just add a number with units of time to a time stamp” and… it worked

By: Ton Plomp

Ton Plomp — Fri, 08 Jun 2007 14:43:04 +0000

Who told you that?
mindblowing!

It are the little things that make life easier

Ton