case which is compact, light weight, and controls the FWD operation. It

also serves as a power supply unit for the HP-85 computer.

 The system processor performs scanning and conditioning of the 8

transducer signals (1 load + 7 deflections). It also monitors the

status of the FWD unit to insure correct measurements.

3.2.3 The HP-85 Computer

 The Hewlett-Packard Model 85 computer is used for input of control

and site/tests identification data as well as displaying, printing,

storing (on magnetic tape), editing, sorting, and further processing of

FWD test data (34,110).

3.2.4 Testing Procedure

 The automatic test sequence is identified and programmed from the

HP-85 keyboard. This includes the input of site identification, height

and number of drops per test point, pavement temperature, etc. When the

operator enters a "START" command, the FWD loading plate and the bar

carrying the deflection transducers will be lowered to the pavement

surface, the weight will be dropped from the pre-programmed heightss,

and the plate and bar will be raised again. An audible "BEEP" signal

tells the operator that the sequence is complete, and that he/she may

drive onto the next test point. A complete measuring sequence normally

takes about one minute, exclusive of driving time between test points,

for three or four drops of the falling weight (34,110).

 The measured set of data (1 load + 7 deflections) will be displayed

on the HP-85 for direct visual inspection, and the data will be stored

on the HP-85 magnetic tape cartridge, together with site identification

information, etc. The display, printed results, and stored results can

be in either metric or English units (34).