User's Guide
Power Transducer
Review I
KRON Instrumentos Elétricos
12
Analog Output
A transducer's principle is supplying a proportional linear output to an input
signal. The power transducer is intended to measure active power (W) and/or reactive
power (VAr). The output signal is always in direct current (D.C.). Thus:
Apparent power = V x I
Active power = V x I x cos φ
Reactive power = V x I x sen φ
And the output signal expresses the power value in a linear manner, as seen
below:
Example of input x output graph in a transducer with 12000W as full scale and
4-20mAdc output. Note that under 0W we have 4mAdc in output and under 12000W,
we have 20mAdc in output.
Regarding the output types, there are two models:
1.
Current type signal
It is a signal in the form of current. This is widely used in systems where the
module that will receive the signal is away from the transducer, once the voltage type
output transducer signal would suffer attenuation and consequent incorrect reading
due to the distance. The 4-20mAdc signal is an interesting manner to check if the
transducer is, indeed, working, as even if there is no input or if it equals 0, it should
provide a 4mAdc output.
