HP 5961-0509 manual Pen Status and Location

Pen Status and Location

Since printing vector graphics has traditionally been performed with plotters, the terms pen and pen position are used to described the HP-GL/2 cursor, the current active position (CAP) when in HP-GL/2 mode. Like a physical pen, this imaginary pen must be selected if you want to draw images. Commands such as Pen Up (PU) or Pen Down (PD), and phrases such as “current pen position” or “moving the pen” apply to the imaginary pen just as they would a physical pen on a plotter.

	Pen Status
	Pen status refers to whether the “pen” is up or down. Use the Pen
	Up (PU) command with X,Y coordinates to move the pen to the
	desired printing location without drawing a line. Use the Pen Down
	(PD) command with X,Y coordinates to lower the pen and begin
	drawing from the current location to the first specified X,Y coordinate.
	Upon entering HP-GL/2 mode for the first time following a reset (ECE)
	command, no pen has been selected and the pen is up. This means
	that no lines are drawn when HP-GL commands are given until a pen
	is selected. This can be done using the Select Pen (SP) command.
	Most drawing commands require that the pen be lowered to produce
	marks on the page. Once lowered with a Pen Down (PD) command,
	the pen remains down for subsequent HP-GL/2 printing commands
	until a Pen Up (PU) or Initialize (IN) command is issued. The pen
	remains selected until a new SP command is received. You must be
	aware of the pen’s up/down status to avoid drawing stray lines
	between parts of your picture.
Note	Upon entry into HP-GL/2 mode, a good programming practice is to
	select a pen and command a pen-up move to the initial starting
	position. This ensures that a pen is selected and is in the proper
	position to begin drawing.
	Every time you use a PU or PD command, the printer updates the
	pen up/down status. The following table shows the commands that
	include an automatic PD command as part of their function. After
	performing their complete function, they return the pen to its previous
	up/down state.

EN Pen Status and Location 17-21