the microprocessor 233 are an audible tone generating device 245 a keypad 247 a display 249 requisite memory 252 an rs 232 interface 254 a parallel output port 255 a digital to analog converter 256 and an analog to digital converter 258 shown in association with the controller 230 is a personal computer 266 and a printer 268 the keypad 247 permits the user to program the force and or dimensional constraints desired according to preset programs or programs of the user 39 s own devising the display 249 communicates to the user for example prompting or displaying menus or the directions or parameters being introduced via the keypad 247 the rs 232 link 254 communicates between the microprocessor 233 and the pc 266 the printer 268 is connected to the microprocessor 233 via the parallel output port 255 the digital to analog converter 256 enables the use of a chart recorder or other analog output device and the analog to digital converter 258 enables programming an experiment based on an analog input the transducer module microprocessor 218 has three basic functions first it controls and coordinates the digital conversion of the analog signals from the strain gauges and lvdt second it processes commands coming to it from the microprocessor 233 of the controller 230 via serial communications links 235 and 227 third it sends digital force and position readings back to the controller 230.