HP 50g Graphing Calculator - Manual (Page 751)

Page 22-36
separate variables in the calculator. These sub-programs are then linked by a
main program, that we will call MOHRCIRCL. We will first create a sub-
directory called MOHRC within the HOME directory, and move into that
directory to type the programs.
The next step is to create the main program and sub-programs within the sub-
directory.
The main program MOHRCIRCL uses the following sub-programs:
Θ INDAT: Requests input of σx, σy, τxy from user, produces a list σL =
{ σx, σy, τxy} as output.
Θ CC&r: Uses σL as input, produces σc = ½(σx+σy), r = radius of
Mohr’s circle, φ n = angle for principal stresses, as output.
Θ DAXES: Uses σc and r as input, determines axes ranges and draws
axes for the Mohr’s circle construct
Θ PCIRC: Uses σc, r, and φ n as input, draw’s Mohr’s circle by producing
a PARAMETRIC plot
Θ DDIAM: Uses σL as input, draws the segment AB (see Mohr’s circle
figure above), joining the input data points in the Mohr’s circle
Θ σLBL: Uses σL as input, places labels to identify points A and B with
labels “ σx” and “σy”.
Θ σAXS: Places the labels “σ” and “τ” in the x- and y-axes, respectively.
Θ PTTL: Places the title “Mohr’s circle” in the figure.
Running the program
If you typed the programs in the order shown above, you will have in your sub-
directory MOHRC the following variables: PTTL,
σAXS, PLPNT, σLBL, PPTS,
DDIAM. Pressing L you find also: PCIRC, DAXES, ATN2, CC&r, INDAT,
MOHRC. Before re-ordering the variables, run the program once by pressing
the soft-key labeled
@MOHRC. Use the following:
@MOHRC Launches the main program MOHRCIRCL
25˜ Enter σx = 25
75˜ Enter σy = 75
50` Enter τxy = 50, and finish data entry.