Page 7/9

28February2018/Version 0 LEM reserves the right to carry out modifications on its transducers, in order to improve them, without prior notice

www.lem.com

DVC 1000-P

Sensitivity and linearity

To measure sensitivity and linearity, the primary voltage (DC)

is cycled from 0 to V

P M, then to −VP M and back to 0 (equally

spaced V

P M/10 steps).

The sensitivity G is defined as the slope of the linear regression

line for a cycle between V

P M.

The linearity error ε

L is the maximum positive or negative

difference between the measured points and the linear

regression line, expressed in % of the maximum measured

value.

Offset

The offset voltage V

O is the residual output voltage when the

input voltage is zero.

The temperature variation V

O T of the offset voltage VO is the

variation of the offset from 25 °C to the considered temperature.

Overall accuracy

The overall accuracy X

G is the error at V

P N, relative to the rated

value V

P N.

It includes all errors mentioned above.

Response and reaction times

The response time t

r and the reaction time tra are shown in the

next figure.

Both depend on the primary voltage dv/dt. They are measured

at nominal voltage.

Figure 13: response time t

r and reaction time tra

The schematic used to measure all electrical parameters is:

Figure 12: Standard characterization schematic for

voltage output transducers

Transducer simplified model

The static model of the transducer at temperature T

A is:

V

S = G⋅VP + ε

In which

ε

= V

O E + VO T (TA) + εG⋅G⋅VP + εG T (TA)⋅G⋅VP + εL⋅G⋅VP M

V

S

: secondary voltage (V)

G

: sensitivity of the transducer (V/V)

V

P

: primary voltage (V)

V

P M

: primary voltage, measuring range (V)

T

A

: ambient operating temperature (°C)

V

O E

: electrical offset voltage (V)

V

O T (TA)

: temperature variation of V

O at

temperature T

A (V)

ε

G

: sensitivity error at 25 °C

ε

G T (T

A)

: thermal drift of sensitivity at

temperature T

A

ε

L

: linearity error

This is the absolute maximum error. As all errors are

independent, a more realistic way to calculate the error would

be to use the following formula:

Performance parameters definition

2

∑

=1

=

ε

ε

������������

N

������������

V

S

t

r

t

ra

t

90 %

10 %

100 %

V

P

V