C130 ABB

C130    ABB    

Current format 4-20 mA

The analog inputs IW62.02 and IW62.03 can also be used for measuring currents from 4...20 mA. To do this, the input must be bypassed by a shunt.

At the same time, it is necessary, to convert the measured input value into the corresponding current value. Here, mathematical function blocks can be used. In particular, the FKG function block can be configured (just two couples of points are enough).

In order to determine the value of the shunt, it is at first necessary to read the data sheet of the used current sensor. The max. external load resistance is important. It must never be exceeded.

In all cases, the shunt should not be greater than 500 Ω. Dependent on the chosen shunt, the following resolution applies:

R = 500 Ω:   4...20 mA generate 2...10 V,

resolution = ca. 11 bits R = 250 Ω:   4...20 mA generate 1...5 V,

resolution = ca. 10 bits

R = 125 Ω:   4...20 mA generate 0.5...2.5 V,

resolution = ca. 9 bits

Temperature format at the analog inputs

The analog input IW62.04 can be used with temperature sensors like Pt100, Pt1000, PTC etc. The analog input can also be configured individually in a lot of different temperature modes. The appendix shows tables containing the relationship between the resistance values and the analog values.

The configuration is performed by the FKG function block. This function block allows the user to define a curve by n points (X0 / YO… Xn-1 / Yn-1) and performes a linear interpolation between the defined points. The resulting curve, representing the relationship between X and Y, gives the current analog value.

- X  corresponds to the current analog value of IW62.04

- Y  is the value according to the table "Resistance / Analog value

The FKG function block is decribed in detail in the function block library.

RDCU-12C

REF542PLUS

REF610

REF615C

REF615C-D

REF615E-D

RET670

REX010

RF620

RMIO-01C

RMIO-12C

RPBA-01

RUSB-02

RVC6-5A

S3N 3P 150A

S503X

SA801F

SA811F

SAFT103