| 摘要 |
<p>A thermocouple 1 is connected to a measuring circuit 410 for measuring its electrical insulation resistance. A sense resistor R1 in the measuring circuit has a first terminal M1 connected to the thermocouple and a second terminal M2 selectively connected to ground via switch S1 or to a known voltage source VS via switch S2. A voltage sensor 412 makes a first measurement of the voltage across sense resistor R1 when it is connected to ground and a second measurement when it is connected to the known voltage source. The insulation resistance of the thermocouple can be calculated from the two voltage measurements. The measuring circuit may be part of an integrated circuit 415 that includes a terminal P1 for insulation resistance measurement and two terminals P2 and P3 for normal measurement of the thermocouple voltage for determining temperature with a voltage sensor 411. During temperature measurement switch S3 is closed to ground the thermocouple.</p> |
