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4 recurring function test – KROHNE OPTISWITCH 3300C NAMUR EN User Manual

Page 22

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Note:

The mode on the NAMUR amplifier must be set so that the

switching output goes to safe condition in case a fault

message is received (I <=1 mA).

Level

Signal current -

Sensor

Control lamp

Falling characteris-

tics max.

>=2.2 mA

Falling characteris-

tics max.

<=1.0 mA

Rising characteris-

tics min.

>=2.2 mA

Rising characteris-

tics min.

<=1.0 mA

Failure

any

<=1.0 mA

flashes

6.4 Recurring function test

According to IEC 61508.
OPTISWITCH 3300 C is qualified in mode A (overfill

protection) for use in measuring chains of stage SIL2

according to IEC 61508 (redundant, stage SIL3).

The following instrument combinations meet the requirements

according to SIL:
OPTISWITCH 3300 C

l

Oscillator VBE60N

The recurring test according to IEC 61508 can be carried out

by pushing the simulation key on the oscillator or by briefly (>2

seconds) interrupting the cable to the sensor. The correct

SIL

Recurring function test

22

OPTISWITCH 3300 C - with NAMUR output

Set up

31358

-EN
-060830