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steners are 
also minimized and standardized. Simple hand tools are 
all that is required to install a system. 
c. Disturbance to the instrument 
All systems with the exception of the B8/B8S and Jena 
SMG encoding systems will not disturb the calibration of 
the instrument. Some systems are so simple that a User 
may self-self-install with only simple hand tools. 
Encoding systems have been developed for the following 
instrument types: 
Table 2 
  
Instruments Encoding Comments 
  
WILD A7 3-Axis RIL supports free motion 
WILD A7 3-Axis R no free motion measurement 
WILD A8 3-Axis RIL supports free motion 
WILD A8 3-Axis R no free motion measurement 
WILD B8/B8S  4-Axis L 
WILD A10 3-Axis R/L supports free motion 
WILD AG1 3-Axis L 
ZEISS D2/3 3-Axis R/L 
ZEISS E2/3 3-Axis R/L 
ZEISS F2/3 4-Axis L 
Jena 3-Axis R 
Topocarts 
4-Axis L 
Jena SMG's 3-Axis R 
SANTONIG6  3-AxisR 
3-Axis encoding in the model space 
Xy. 
4-Axis encoding in the photo space 
Xy xy 
R encoding with rotary encoder 
L encoding with linear encoder 
  
For hand-wheel instruments with free motion capabilities such as 
WILD A7's, A8's & A10's, two versions of encoding are available. 
The simpler version (3-Axis R) is mounted on the instrument gear 
box and does not support free motion while a more advanced 
version utilize linear encoders mounted along the model stage 
lead-screw providing for continuous encoder count whether the 
instrument is in free motion mode or not. 
Most of the encoding mounting hardware utilize existing holes 
already drilled in the instrument chassis. Sometime holes 
83 
exposed after removal of a sub-component in the instrument are 
utilized. 
3.3 WIRING HARNESS 
ISM makes extensive use of modern plastic wiring harnesses 
available for the computer or telecommunication industry. For 
example, standard RJ-11 telephone jacks are use to connect 
encoder leads to the main cables so that positive connections and 
easy removal are achieved. This will also eliminate soldering of 
wiring which is prone to breakage if handled carelessly. The 
ultimate objective is total system reliability. 
The wiring harness gathers the multitudes of fine wiring into a 
convenient bundle terminating in a common connector such as 
RS232 or D50. The 50 pin D50 is most commonly used because 
it cannot be confused with any connectors or ports found in a 
modern computer. 
4.0 INTERFACE DEVICES 
Interface devices have been available from major 
manufacturers for some time, however these devices were 
typically designed for coordinate data recording in the 
mensuration process for aerial triangulation. For example, 
WILD offered EK-5, and later EK-22, which were commonly 
delivered with the A7, A8 & A10 models. Such devices can 
convert the signals from the encoders into co-ordinate values 
(typically model co-ordinates) for aerial triangulation programs. 
These devices are bulky, troublesome and by-and-large 
obsolete. The modern equivalent is a simple solid state 
digitizing "card" for the computer CPU. 
Digitizing cards were not originally designed for 
photogrammetric instrument up-grading. They can be found in 
other digital applications as part of the controlling system. For 
example, numerically controlled machine tools such as a 
milling machine might utilize a 3 channel card to control the 
"longitudinal feed", "cross feed" and "milling depth" of the 
cutting tool. Such a 3 channel card may also be used to 
accept model co-ordinate (x,y,z) inputs. 
In the course of time various computers ranging from "mini's", 
Workstations and PC have been used for instrument 
upgrading, however this field has been dominated by Personal 
Computers ever since the introduction of the Intel 80286 based 
systems. Manufacturers such as Altec have been supplying 
digitizing cards for some time, but the most popular card is the 
"SEC-PC" Card manufactured by Fischer Computer Systems 
for the PC-AT bus. This card is used by almost all vendors in 
this field.