HP 50g - displaying result in engineering format



#2

I have a few soft menus setup in a directory in my CST menu that allow a quick way to change results from standard to fixed decimal to engineering with three or six decimal places, etc. What I'm wondering is if there is a way to change how a result is displayed in engineering format.

For example, a result I calculated a second ago gave 1285714.28571 all good and well but I wanted to see that in engineering format. I tell my machine to convert to ENG with three decimal places and it spits back 1.286E6 exactly as expected. But is there a way to make it give the result as E3? ie: 1285.714E3 ?

This is pretty trivial as it is simply a sliding of the decimal place but being such a highly programmable machine and I would hate to make a silly mistake like moving the decimal the wrong direction or something on an exam when time is valuable, I was hoping for a way to let the 50g do the work for me.

Any thoughts?


#3

Hi,

I know what you mean. Although it may seem trivial, it IS very important that you see those numbers quickly and correctly.

I'm pretty sure the 50G has "ENG" as a display format in the mode menu.

I don't have my 50G handy, so maybe you can check and see and get back to me.

Hope this helps,
Dan

#4

I have to admit I never even touched a 50G, but I wonder if it does not offer a feature that's even available on my 35s: There are two keys labelled "->ENG" and "ENG->" that temporarily display the current X-value in engineering notation while the user may change the power of ten resp. move the decimal point/comma:

   9E6 [ENTER]
7 [/] 1285714,28571
 
[ENG->] 1,28571428571 E6
[ENG->] 1285,71428571 E3
[ENG->] 1285714,28571 E0
[ENG->] 1285714285,71 E-3
[->ENG] 1285714,28571 E0
[->ENG] 1285,71428571 E3
[->ENG] 1,28571428571 E6
[->ENG] 0,00128571428571 E9
[->ENG] 0,00000128571428571 E12
 
[<-] 1285714,28571
As you can see, the display is not rounded to four significant places, as you would prefer. The display always shows all digits. But otherwise everything works as you demanded. Does the 50G not offer something like this? If not, a short program should do the trick.

Dieter


#5

Thanks for the reply, I don't see any commands in the catalog for what you're showing me. The only one I know of is just "ENG" and you have to supply it with how many decimal places you want displayed. << 3 ENG >> will turn a result into engineering notation with three decimal place accuracy.

I'm still pretty new to this 50g, and HP calculators in general as this is my first. I'll mess around and see if I can get a program working that will do what I'm after!


#6

I don't have my manual in front of me, but I believe the ENG shows significant digits of the mantissa, not decimal places. So ENG 4 would show four significant digits and move the decimal place to get the require exponent as a multiple of three.


#7

We are talking about two different things here.

  • The ENG display format. This is available on every scientific HP since the mid-seventies I know of. ENG n displays n+1 (!) significant digits and an exponent that is an integer multiple of three. For instance, in ENG 3 the value of 10000 Pi is displayed as 31,42 E 3. Of course this is also available on the 50G, and Sean already uses it.
  • Some calculators feature another command that temporarily (!) displays a number in engineering notation, no matter what display mode is currently set. Here, repeated use of this command ("ENG>" resp. ">ENG") allows the user to switch through various equivalent displays with different powers of ten (still always a multiple of three). So if you evaluated an electric power to 23,4 Watts, you may have this displayed as 23400 E-3 = 23400 mW or as 0,0234 E3 = 0,0234 kW. That's what Sean is looking for.

Dieter


#8

Yes that is exactly the functionality I am looking for. I haven't been able to get that command to work on the 50g though. I guess it's not available.


#9

Sorry, I see your question but I don't understand the underlying problem. If you get a result of e.g. 123.4 N you know by counting digits that this equals 0.1234 kN or 123400 mN, so what? Counting problems??

d:-?

#10

Rather than using ENG mode, perhaps you can achieve what you want with the units commands utilising the appropriate prefixes for mu, pico etc.

Nick

Edited: 22 Nov 2013, 1:35 p.m.


#11

Following Walter's example, on the HP-28S you would do the conversion as follows

4:
3: 1.234
2: 'N'
1: 'mN'

[CONVERT]

yielding the result
4:
3:
2: 1234
1: 'mN'

with STD set as the display mode. The HP48 family onwards reimplemented the units facility, but the basic idea of adding a prefix to the unit being converted to will be the same.

Nick

Edited: 24 Nov 2013, 12:01 p.m.

#12

Hello.

Quote:
For example, a result I calculated a second ago gave 1285714.28571 all good and well but I wanted to see that in engineering format. I tell my machine to convert to ENG with three decimal places and it spits back 1.286E6 exactly as expected. But is there a way to make it give the result as E3? ie: 1285.714E3 ?

I get the same issue a few years ago on my HP-28S trying to keep ENG format using a fix 10x's unit in order to facilitate comparison of displayed results. I use this simply trick to force the results to be display or print as part of millions:

Keeping the general format mode in STD or in any FIX mode

« EE6 / 'EE6' * »
where of course a EE6 variable exists storing 1.E6.

Your example 1285714.2857 will be displayed as '1.2857*EE6' in 4 FIX mode. A simple evaluation will compute the number back to 1285714.2857

I sure you can adapt my little code to your expectations. And you are welcome to do so !


Edited: 24 Nov 2013, 5:48 a.m.


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