plot formatting on an HP 82162A printer

[4ster]

I've put together a little test rig that tests function of oxygen sensors in a rebreather. The output is recorded on an HP 82162A thermal printer. It is printing results from an HP 41 program. I'm having a small problem with plotter formatting of small numbers using REGPLOT. (I know, who plots on these anymore when there are such better options?)

Here is a sample output for two sensors:


Essentially, the deviation percentage from the expected value at different pressures of oxygen is what is being plotted. Zero is a perfect reading for each pressure.

In the picture above: On the first plot the third sample deviation is small, less than 0.1%, so the calculator switches into engineering notation. That throws the plot formatting off. I would rather the calculator round this number to 0.0 and preserve formatting.

During the plotting routine the calculator is set to FIX 1 instead of the default FIX 4 for the PRAXIS subroutine I am using to plot the Y axis.

I'm not a great 41 programer, I've looked in my manuals and haven't yet discovered a flag setting or something that keeps the calculator display out of engineering mode for small numbers.

The sensors being plotted here are older ones that don't perform as well as new ones. A new sensor is more likely to plot near the zero center axis, so there will be a higher likelihood of outputs near zero. Which will make the plot pretty hard to comprehend

One solution is to write a little routine that replaces plotting small numbers with text "0.0". I'm guessing there is a better way I can't think of. I thought it would be worth asking you folks for the face palm solution lurking in the manual.

Thanks,
Steve