Voltage Transducer
- Thread starter Tuck3rz
- Start date
There will be a fixed ratio between the current that flows into the +HT/-HT terminals and the current that flows into or out of the the M (measure) terminal.
For this type LV 25-P the ratio secondary-to-primary Kn= 2.5:1 [2500:1000]
If the primary current is 10mA then the secondary (M terminal) current is 25mA.
The dual supply is (most probably) required to conveniently set the nominal secondary (M) current to zero for zero primary current. It's an intentional consequence of the unit's internal electronic design.
When the device is used as a voltage-to-current transducer, the resistor R1 limits the sensing current drawn from the voltage to be measured.
Suppose you want to measure a full scale DC voltage of 250V. To limit the primary current to 10mA you would need a resistance
R1=250/10mA-Rp = 25kΩ-250Ω=24.75kΩ
where Rp=primary resistance=250Ω [see the data sheet]
Rm is the sensing resistor in the M terminal used to convert the M terminal current Is into a sensible voltage. One side of Rm connects to the 0V terminal of the power supply - which can be conveniently set as the signal ground or reference. If Rm=100Ω in the example being considered, then the output voltage across Rm would be 25mA x 100Ω = 2.5V @ 250V on the high voltage side (@ 10mA primary current).
For this type LV 25-P the ratio secondary-to-primary Kn= 2.5:1 [2500:1000]
If the primary current is 10mA then the secondary (M terminal) current is 25mA.
The dual supply is (most probably) required to conveniently set the nominal secondary (M) current to zero for zero primary current. It's an intentional consequence of the unit's internal electronic design.
When the device is used as a voltage-to-current transducer, the resistor R1 limits the sensing current drawn from the voltage to be measured.
Suppose you want to measure a full scale DC voltage of 250V. To limit the primary current to 10mA you would need a resistance
R1=250/10mA-Rp = 25kΩ-250Ω=24.75kΩ
where Rp=primary resistance=250Ω [see the data sheet]
Rm is the sensing resistor in the M terminal used to convert the M terminal current Is into a sensible voltage. One side of Rm connects to the 0V terminal of the power supply - which can be conveniently set as the signal ground or reference. If Rm=100Ω in the example being considered, then the output voltage across Rm would be 25mA x 100Ω = 2.5V @ 250V on the high voltage side (@ 10mA primary current).
Yes - correct.
