Weird Units Conversion

[MattGreer]

If I convert 1_Mft to 1_ft, I get (added commas for clarity) 1,000,000_ft

If I convert 1_Mft^3 to 1_ft^3, I get 1.E18_ft3.

What's going on?

I'm trying to set something up to convert 1 MMscfd to 1 scfm. So "one million standard cubic feet per day" to "standard cubic feet per minute". Volumetric flow. I can do this by hand easy of course but I like mucking with the calculator.

What am I missing?

[Thomas Okken]

The prefix applies to the base unit. So, for example, a cubic centimeter a.k.a. cc, or cm^3, is [one centimeter] cubed or one millionth of a cubic meter, and not one centi-[cubic meter].

[MattGreer]

I see!

So how would I go about creating a custom unit "Million Cubic Feet"? I've not tried that before...

Thanks for your help!

[Thomas Okken]

It's highly unconventional, but hft^3 appears to work, "cubic hectofoot."

[Giuseppe Donnini]

1. 1000000_ft^3 'Mcbf' STO
   (Store the unit object 1000000_ft^3 into the variable Mcbf or whatever name you want to assign to your new unit).
    
2. { 1_Mcbf } TMENU
   (Add any units you want to the list. Note that it is not sufficient to put the name of the unit into the list, you must use a full unit object, e.g. if you want to add ft^3, put 1_ft^3 into the list).
   

This produces a menu key for your new unit with the same functionality as a built-in unit menu key, i.e.:

   [Mcbf]  multiplies by the new unit;
LS+[Mcbf]  converts to the new unit;
RS+[Mcbf]  divides by the new unit.

Try  5000000_ft^3 LS+[Mcbf], and you will get the expected result of  5_Mcbf.

Note that this new unit is a simple, non-compound unit which may itself be prefixed with any SI prefix.

[MattGreer]

You guys are amazing. Thank you!

[MattGreer]

Giuseppe,

I'm considering upgrading to either a 50G or a Prime. My limited understanding of the Prime is that it's very different when it comes to storing variables and especially with units conversions.

What you described above, can that be done with the Prime? One thing I've definitely taken advantage of with the 48GX is the CST menu with many combinations of custom units. I'm hoping I can do the same with the Prime, but I'm hearing that's not very possible?

[Marco Polo]

(09-09-2019 05:05 AM)MattGreer Wrote:  Giuseppe,

I'm considering upgrading to either a 50G or a Prime. My limited understanding of the Prime is that it's very different when it comes to storing variables and especially with units conversions.

What you described above, can that be done with the Prime? One thing I've definitely taken advantage of with the 48GX is the CST menu with many combinations of custom units. I'm hoping I can do the same with the Prime, but I'm hearing that's not very possible?

AFAIK no. That's why I still use a 50g and don't plan to switch to Prime.

[Claudio L.]

(09-09-2019 04:57 PM)Marco Polo Wrote:  

(09-09-2019 05:05 AM)MattGreer Wrote:  Giuseppe,

I'm considering upgrading to either a 50G or a Prime. My limited understanding of the Prime is that it's very different when it comes to storing variables and especially with units conversions.

What you described above, can that be done with the Prime? One thing I've definitely taken advantage of with the 48GX is the CST menu with many combinations of custom units. I'm hoping I can do the same with the Prime, but I'm hearing that's not very possible?

AFAIK no. That's why I still use a 50g and don't plan to switch to Prime.

I agree. If custom units is your thing, you can't beat the 50g... until you install newRPL of course
EDIT: Back up that wink with a link.

[MattGreer]

(09-10-2019 10:30 PM)Claudio L. Wrote:  

(09-09-2019 04:57 PM)Marco Polo Wrote:  AFAIK no. That's why I still use a 50g and don't plan to switch to Prime.

I agree. If custom units is your thing, you can't beat the 50g... until you install newRPL of course
EDIT: Back up that wink with a link.

I'm confused, are you saying you can't beat the 50g, until you have a 50g?

[Giuseppe Donnini]

I totally agree. This is one of the many reasons why the HP Prime has absolutely no appeal to me.

However, it is only fair to mention that Didier Lachièze developed a program for the HP Prime, called Units48, which tries to mimick the HP-48 unit management.

See here: https://www.hpcalc.org/details/8911