in the modules. Other conductors in the cable will be: 

 seven gage-selection control wires; one or two calibration 

 control wires; and one conductor for returning the gage 

 signal. 



The gage-selection control consists of a timer which 

 generates pulses at two-second intervals, a seven-bit binary 

 counter which operates seven relays in such sequence as to 

 range through all the binary digits from 0000000 to 1111111, 

 and a 3-digit decimal counter the function of which is to reset 

 the binary counter after the latter has covered the range that 

 includes the total number of instrument packages. Each of 

 the relays, when operated, sends a CW signal derived from the 

 power supply down one of the seven gage-selection control 

 wires. The combination of seven "on" or "off" CW signals 

 is decoded in each package in such a way that only one of 

 the packages sends back an FM gage-reading signal. Provision 

 is made for a manual reset of the binary counter and for 

 manual selection of the binary-coded sampling signal. 



Thus, in automatic operation, the control circuit interro- 

 gates the whole chain at the rate of one reading each two 

 seconds and automatically repeats the cycle. The operation 

 may be interrupted and varied manually at any time. 



Since the primary purpose of this study was to determine 

 the feasibility of obtaining data from a chain of sensors 



86 



