/ 
Fig. 3 Position of photogranhs in DP—1 Fig. 4 bx-rail in DP—1 
An interesting desiga detail is the solution chosen for the bx-adjustment (Fig. 4). Here the base rail 
BS is rotated so that the plotting cameras are displaced by means of the inclined ball bearings KL. 
e e The bx-rail is at the same time the axis of rotation for 
w-adjustment. In the same connection mention may be 
made of the design of the z-rail (Fig. 5) which in spite of 
the use of simple drawn material is of surprisingly high 
accuracy. The fact that in this instrument, as in the sec- 
ond-order Planimat plotter, the axes of rotation for the ¢ 
and w-motion do not intersect the perspective center but 
have been given a more favorable position from a design 
point of view, is intended to reduce the instrument out- 
lay, to increase its stability and to facilitate orientation 
(see below). 
A few technical data may suffice to supplement 
the above information: 
Calibrated focal length of standard equipment: 6” (153 mm) 
Useful magnification ranges for practically distortion-free projection: 
Type A lens — 2.5x (depth-of-field range 2.0 to 3.0%) 
Type B lens — 2.0x (depth-of-field range 1.6 to 2.4x) 
Type C lens — 1.6x (depth-of-field range 1.3 to 1.9x). 
  
Fig. 5 z-rail in DP—] 
®, €, N-ranges: + 5° 
bx-range: 130 to 325 mm 
z-scales: interchangeable (1 : 5,000; 1 : 10,000 and 1 : 25,000) 
& Elevation measurement: reading to 0.01 mm on instrument scale 
e Projection surface: 60 x 80 cm 
Diameter of measuring mark: 0.4 mm 
Lens apertures: 1/22 {1/80 
Fig. 6 completes these data. 
3. Plotting techniques 
On account of its design, the DP-1 is suited for the following plotting techniques: 
Method 1: 
Conventional mapping with the aid of a plotting table, the model being viewed through filter 
spectales. The objects to be plotted are delineated by means of the floating mark and simultaneously 
plotted on paper (or scribed) with the aid of the graphical tool in the plotting table. 
Method 2: 
No use is made of the plotting table. The image is projected directly onto the instrument table. The 
| pencil point is used as measuring mark.