SELF-POWERED DEVICE FOR THE AUTOMATIC PROCESSING OF ANALOGIC SIGNALS BY CURRENT SUBTRACTION IN A DEGRESSIVE OR NON-DEGRESSIVE LINEAR LINE

摘要

The invention concerns an electronic circuit carrying out said conversions which is self-powered by a signal which it converts and comprises means for supplying two voltage levels UR1 and UR4 proportional to the current absorbed by (A) and to the current (Is) passing through the charge, and adding them to R2 and R3 in (12) so as to compare them with a reference threshold (10). (A) absorbs a current which is function of the voltage in (9), itself dependent on (Is) passing through R4. The absorbed current will be nil if U12 /= UT by the simple presence of UR4. The potential barrier series-mounted with the charge is permanent with (Z) and automatically reduced with option (F), a authorising self powering of (A) and (T). The subtracted current will be constant for R4 = 0 and in decreasing scale for R4 0, authorising self-powered conversions such as: 4 mA to 20 mA = 0 to 20 mA; 4 mA to 20 mA = 0 to 10 V ( with charge of 500 OMEGA ); 4 mA to 20 mA = 0 to 16 mA; 4 mA to 20 mA = 2 to 18 mA.