ABB Low Voltage Components - Industrial & Commercial

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ABB Low Voltage Industrial Products 0312

Nearly every process includes a control system that receives

data by means of analog signals and then evaluates the data

and sets the respective parameters correspondingly.

When transmitting analog signals numerous problems may

arise which can disturb or even block an ideal behavior of the

process.

Below we have listed some processing problems together

with the respective solutions to solve these problems:

Signal conversion

Sometimes the available signals cannot be processed by the

controller or the actuator. In this case, signal converters are

required to convert the input signal (or different input signals)

to the desired output signal.

Signal amplification

If long lines or high burdens have to be operated, it may be

necessary to amplify the signal. CC analog signal converters

require only low input power and provide high output power.

Thus, there are no restrictions for the converter's position on

the line, i.e. it can be used

− for signal refreshing at the end of the line (low input

power)

− or for signal amplification at the beginning of the line

(high output power).

Signal filtering

Particularly on long lines or in rough industrial environments

the signals are exposed to high electromagnetic interferences.

The frequency of the coupled interference signals may be in

the range of the common mains frequency (50 Hz) or even much

higher (in case of frequency converters). According to the

specific requirements, analog signal converters are available

which provide reliable suppression of those interferences by

means of an input low-pass filter.

Applications for analog signal processing and correct

solution using CC-E and CC-U converters

Signal separation

Protection against overvoltage

The increased use of micro-electronics make controls much

more sensitive against overvoltages, resulting from lightning

discharges or switching processes. Suppression diodes are

incorporated in the input of the CC analog signal converters

which enable the converters to arrest overvoltages with low

energy level (resulting from switching processes) by them-

selves. The products furthermore provide electrical isolation

between input, output and supply circuit for protection of the

controller connected to the output.

Protection against ground loops

If components are used which refer to ground, the measuring

signals can be falsified by a so-called ground loop. In this

case, certain parts of the signal are transmitted via earth and

not via the analog transmission line, thus causing incorrect

evaluation of the signal. The electrical isolation between the

input and the output disconnects these ground loops and

thus enables correct signal transmission.

Approvals

CC-E/STD

CC-E I/I

CC-U/STD

CC-U/STDR

CC-E/RTD

CC-U/RTD

CC-U/RTDR

CC-E/TC

CC-U/TC

CC-U/TCR

CC-E/I

CC-E I

/ILPO

CC-U/I

CC-U/V

existing

for some

devices

pending

UL 508, CAN/CSA C22.2 No.14

UL 1604 (Class I, Div 2, hazardous locations),

CAN/CSA C22.2 No.213

CB scheme

CCC

Marks

C-Tick

0-10 V

100 m 0-20 mA

100 m 4-20 mA

2CDC 282 013 F0206

Controller

e.g. AC500

Measuring sensor

Actuator

Analog signal converter

(e.g. CC-E or CC-U)

Analog signal converter

(e.g. CC-E or CC-U)

Analog standard signal converters

Application, approvals & marks