CLT3-4B

Characteristics

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The current limiting circuit connected between the input and the output pins is compensated

all over the temperature range. Thanks to its low tolerance, the current limitation allows

reducing drastically the dissipation of the input compared to a resistive input: the overall

module requires less cooling capability and becomes smaller.

The output block of each termination channel controls the operation of an opto-coupler that

is enabled by a Light Emitting Diode.

When the input current is less than 1.5 mA, this output circuit derivates the input current to

maintain the opto-coupler off.

The original structure of the CLT limiter allows its activation threshold to be low and

insensitive to the output voltage up to a maximum value of 2.0 V.

current (3/4) is higher than 1.5 mA. The whole termination channel including the opto-

coupler is on.

Depending on the input type operation that is described by the IEC 61131-2 standard, the

This document describes operation and characteristics for type 3 operation with

1.2

Input characteristics of CLT3-4

Figure 4.

Typical input characteristics of each CLT3-4 channel

30

25

20

15

10

5

0

30

5

3.7

0

0.5

1

1.5

2

2.5

3

3.5

4

V (V)

IN

I (mA)

IN

Off-state

On-state