PLOTTER Plotters are output devices like printers. They also

produce hard copy of the output data. The only difference in plotter and printer is that printer produces text output as well as graphical images both while the plotter is used to produce drawing like engineering applications etc. One or more pens are used with plotter for producing these drawing images on paper.

TYPES OF PLOTTERS

SINGLE PEN PLOTTERS

MULTIPLE PEN PLOTTERS

(On the basis of no. of pens used)

SINGLE PEN PLOTTER

The single pen plotter contains a single pen into pen holder which can be changed manually. The single pen plotter will consume more time and method used by it may be mare frustrating as compared to multiple pen plotter.

MULTIPLE PEN PLOTTER The multiple pen plotter contains a main pen holder and a

pen changing assembly. The pen that is drawing is holded by the main pen holder and rest pens lie in the assembly. The main holder collects different pens from the pen assembly as they are needed automatically. For this, the computer supplies instructions to the main pen holder.

TYPES OF PLOTTERS

DRUM PLOTTERS

FLAT BED PLOTTERS

(On the basis of pen interaction methods)

DRUM PLOTTERS

In a drum plotter the paper is placed between a drum and a platen which holds the paper. The paper moves up and down vertically and the pen moves left and right horizontally. Any required shaped graph or image can be plotted on paper using these movements.

For plotting a picture image the paper moves up and down multiple times in a drum plotter and this reduces over all accuracy of the plotter.

FLAT BED PLOTTERFlat bed plotters are rectangle shaped open box type instruments. They are made bigger than the largest sized paper. It contains a pen assembly in which additional pens are arranged. A main pen holder contains the currently working pen. The holder bar, moves back and forth along X-axis and the pen on holder moves back and forth along Y-axis to plot an image. The paper remains fixed at its place.

They can plot any sized images, smaller as well as larger with same accuracy. The accuracy of flat bed plotter is more then .001 inch. Though the plotter can plot any size image but its size is itself a limit for that. Thus for higher size images the drum plotter is a better option.

The pen speed of these plotter is 15 to30 inches per second and they are slow for complex graphical images like CAD applications.

WORKING PRINCIPLES OF PLOTTERS

The pen plotter use one or multiple pens plot the image on the paper. Their speed varies between 15 to 30 inches per second of pen lines. The wholes image to be plotted is controlled by various instructions used by the computer as a series in one of the plotter control language.

If it is a Single pen plotter Single pen plotter and drawing contains only one color then the plotting is fastest. The pen draws the image according to the instructions received from the computer. But if it is a multicolor drawing then one needs to sit there and change the pens as and when required or prompted. This decreases the speed of the plotting and also one has to sit there and watch the job continuously.

On the other hand in case of a Multiple pen plotterMultiple pen plotter the pens are changed automatically by the main pen holder from the pen assembly. The main pen holder collects the pens from assembly as and when required and it acts on the instructions supplied by the computer .

In most of the cases the plotter starts with one pen and draws all portions of drawing of that color then changes the second pen completes the portion of that color. The process continues till all parts with all color of drawing is completed. Because the pen is changed automatically so it is faster than single pen plotter in case of multicolor drawing but it needs an ink that must dry quickly enough so that lines are not subsequently smeared by the pen tip and also ink should not dry on the pen tip. Also all the pens filled with inks must be ready to start the plotting

The plotter are serial devices so they need serial ports for interfacing. Almost all plotters use the 25 pin D shell connectors for their interfacing. The 25 wired cable uses one 25 DM and 25 DF connector at its ends. The female connector is attached to the computer and the male connector is attached to the plotter. Different software's require different cables wiring or pin outs for the plotters.

PLOTTERS CONNECTORS

FEATURES OF PLOTTERS The main features of Plotters are:• They produce hard copy output.• They are used to produce drawings like architectural drawing and

engineering applications in a more efficient way than printers.• A plotter uses pens to draw images on the paper instead of dots

like printer.• It produces smooth and sharp drawing of objects which is not

possible to print using printers.• It is more useful for graphical/drawing outputs and less for text

outputs.• It uses multiple pens to plot colored drawing.• Plotters can plot any size of images with same efficiency and

accuracy.

• Some plotters use pens in a straight line arrangement while some in a circular arrangement.

• Plotters are serial device and are connected through a serial port interface to a computer.

• The pen speed of plotters vary between 15 to 30 inches per second and for complex graphical images it may reduces up to 10 inches per second.

• Plotters moves pen or pencil according to the instruction received from the computer in plotter control language. The most common plotter control language is HGPL i.e. Hewlett Packard Graphic Language. Other languages are DMPL(Digital Microprocessor Plotter Language), HIPLOT(Houseton Instruments Plotter Language) etc.