The Museum of HP Calculators

HP Forum Archive 17

 Simple HP 50g questionsMessage #1 Posted by PhysicsNerd on 5 May 2007, 9:57 p.m. How do you convert decimals to fractions? Is there anyway to reduce the autopower off time? It's too long. How do you erase all of the data (all of the previous calculations and notebook stuff)?? I think it is slowing my calculator down. Thanks!

 Re: Simple HP 50g questionsMessage #2 Posted by Happy HP User on 5 May 2007, 10:08 p.m.,in response to message #1 by PhysicsNerd >How do you convert decimals to fractions? ->Q or ->QPI >Is there anyway to reduce the autopower off time? It's too long. RightShift On turns the machine off. >How do you erase all of the data (all of the previous calculations and notebook stuff)?? I think it is slowing my calculator down. RightShift BackArrow to clear stack.

 Re: Simple HP 50g questionsMessage #3 Posted by Tim Wessman on 5 May 2007, 11:36 p.m.,in response to message #2 by Happy HP User If you'd like to change the auto time-off, store a hexadecimal number in a value named TOFF in your home directory. #(sec*8192)d is the number, so for 15 seconds, it would be #122880d (15*8192). Default time is 5 minutes I think. TW

 Re: Simple HP 50g questionsMessage #4 Posted by James M. Prange (Michigan) on 5 May 2007, 11:37 p.m.,in response to message #1 by PhysicsNerd First off, be sure to have the HP 49g+ & 48gII_Advanced User's Reference Manual; it's available from this HP page. Also have a look at the training modules. Quote: How do you convert decimals to fractions? Of course, for an exact conversion, you could consider the "real" (decimal) number to be the numerator of a fraction with 1 as its denominator, and multiply both the numerator and denominator by whichever is the lowest power of 10 required to make the resulting numerator an integer. Other than that, for approximate conversions, you could try the \->Q, \->Q\pi, or XQ commands. Also try searches of http://www.hpcalc.org/ and http://groups.google.com/group/comp.sys.hp48/ for programs such as PDQ (or maybe PDQ1 or PDQ2) and DEC2FRAC. Maybe read the training module entitled Working with fractions. Quote: Is there anyway to reduce the autopower off time? It's too long. Yes. With any 49 series, store a binary integer up to #FFFFFFFFh (the largest 32-bit integer) in the reserved variable 'TOFF'. This represents the number of ticks (1 second = 8192 ticks) of inactivity before the calculator automatically turns off, with a minimum of 5 seconds as a "safety net". For example, storing #5A000h in TOFF results in a 45-second automatic timed OFF. For a "never-off" mode, an alternative is to store a program that doesn't include the OFF command in the reserved variable 'STARTOFF', which will be run whenever the automatic timed OFF would occur, whether the default 5 minutes or as set by TOFF. But note that STARTOFF won't by invoked by RightShift OFF, which simply invokes the OFF command itself, unless you assign something else to that keystroke. Quote: How do you erase all of the data (all of the previous calculations and notebook stuff)?? I think it is slowing my calculator down. ????? Do you mean how to clear the stack? RightShift CLEAR does that. Of course that simply invokes the CLEAR command. Generally, clear the stack either when you're sure that you're finished with a problem, or just before starting a new problem. If you mean how to purge variables, you can use the PURGE (or for directories, PGDIR) command, or you can use the filer (LeftShift FILES) to purge variables. To purge all variables from the current directory, use the CLVAR command. To clear memory entirely, press and hold [ON], [A], and [F] all at the same time, then release [F] first, followed by the other two keys, to get a TTRM (Try To Recover Memory?) screen. Of course, all of this assumes that you have the 49 series in "RPN" mode, not "ALG" mode. Last but not least, for RPL models, you'd probably do better searching the comp.sys.hp48 usenet group from http://groups.google.com/advanced_search?, or if you can't find the answer, post your question to the newsgroup. RegardsJames Edited: 5 May 2007, 11:46 p.m.

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