Use of Kilo, Mega,Tera in Plus42

[jonmoore]

As I understand things, Thomas based his implementation of Units in Plus42 on the 48's Units implementation.

To be specific, SI Base units aren't the metric system per se, they're the universals for time, length, mass etc. e.g. Much as mm is a metric unit, the SI unit of length is the meter (confusingly, denoted with a lowercase m by SI but with a capital M in HP calculators). The Ubase command converts any unit to its SI unit equivalent, which may not seem so useful on first look, but when you're chaining unit calculations, converting first to SI units ensures you're always calculating like units.

Symbol - Name - Quantity
s - second - time
m - metre - length
kg - kilogram - mass
A - ampere - electric current
K - kelvin - thermodynamic temperature
mol - mole - amount of substance
cd - candela - luminous intensity

Incidentally, I've just checked the Plus42 docs and Thomas has implemented the Ubase command. I don't know what platform you're using Plus42 on, so this next tip may or may not be so practical. On the 48 line of calculators you don't have to go through the the Unit's catalog to input units. You simply type an underscore and the symbol for the unit directly. e.g. 486_mm for millimeters or .486_M for meters.

Here's a link to the relevant section of the Plus42 docs: https://www.thomasokken.com/plus42/#units

However, those docs don't provide the fully skinny for working with units on the Plus 42. For that you'll need to refer to the HP48 series docs:

https://literature.hpcalc.org/items/375 - This is the User Guide and chapter 10 deals with Unit objects.

https://literature.hpcalc.org/items/370 - And this is the Advanced User Guide which has a very handy appendix (B) which shows native 48 units and their SI equivalent. It has to be remembered that vintage HP calculators where primarily designed for the US market, hence the default units in the table are US unit's (however, it's my understanding that internally the calculator uses the SI equivalent).