Comtech EF Data RC-1160 - Manual (Page 66)

Theory of Operation Revision 1
RC-1160 RC-1260 Redundancy Switch Controllers MN-RC1160RC1260
C-6
C.6 Analog Current Sense
All three LNA/LNB current-sensing circuits are identical. Only LNA/LNB 1 will be discussed.
Differential amplifier U14A measures and amplifies the voltage across the 1Ω resistor, R61.
Refer to Figure C-2 for a plot of the voltage at the output of U14A versus LNA/LNB current from 90 to 300
mA. Load currents ≥ 500 mA require setting a jumper shunt across JP2 pins 2 and 3, thus reducing the sense
resistor to 0.25Ω.
Figure C-3. LNA/LNB Current/Voltage Output
The output voltage from U14A is converted to an 8-bit byte by A/D converter U9 and stored in EEPROM U7.