The Circle Instruction, Ci 7 - HP 7470A Interfacing And Programming Manual

The Circle Instruction, CI 7
DESCRIPHDN The circle instruction, CI, provides the means to draw a
circle of a specified radius and chord angle. It is only included in the
instruction set of RS-232-Cplotters that have the serial prefix number
2308Aor higher.
USES The instruction can be used to generate circles with a single
command. All computations are internal to the plotter to reduce com­
puter overhead.
SYNTAX CI radius (, chord angle) terminator
90°
CIRCLE
STARTING POINT:
RADIUS +
1so°—— —— 0"
CIRCLE /'
STARTING POINT:
RADIUS —
CURRENT PEN POSITION
270°
EXPLANATIONThe radius parameter can be a positive or negative
number in integer format. Its sign defines the starting point of the
Circle:a circle with a positive radius starts at the 0—degree p oint; a circle
with a negative radius starts at the 180—degree p oint. The current pen
position is the Center of the circle. If scaling is off, the radius is in
plotter units. If scaling is on, the radius is in user units. If user units
are not the same size in the X-and Y-directions, ellipses will be drawn.
The chord angle parameter is in integer format and governs the
smoothness of the circle. It is interpreted as degrees and sets the
maximum angle subtended by a chord that is drawn to represent an
arc segment of the circle, as shown below. The actual angle used may
be changed by the plotter so that all chords are the same length. The
sign of the parameter is ignored, except to set the maximum 1n—range
limit to —32768 or +32 767.
3-12 CONTROLLING THE PEN AND PLOTTING