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1.3 Instructions on EMI
JetWeb
Important!
Measures for increasing immunity to interfering in electric plants:
The JX3-THI2-RTD module has to be attached to a DIN rail acc. to EN 50022-35
x 7.5.
If correct measurements are required, the sensor cables connected to inputs
X41 and X42 of the JX3-THI2-RTD module have to be looped through a ferrite
core at least once or twice. This way, external interferences can be minimized.
A further reduction of interferences can be achieved by using a round cable
snap ferrite (e.g. by Würth Elektronik, part # 74271222). Tests with an RF
injection (10 V/m) resulted in a higher susceptibility to interference. The
measuring accuracy decreased from 0.5°C to 1.5°C in the range of up to
450°C.
Follow the instructions given in Application Note 016 "EMC-Compatible
Installation of the Electric Cabinet" published by Jetter AG.
The following instructions are excerpts from Application Note 016:
On principle, physical separation should be maintained between signal and
power lines. We recommend spacings greater than 20 cm. Cables and lines
should cross each other at an angle of 90°.
Shielded cables must be used for the following lines:
Analog lines, data lines, motor cables coming from inverter drives (servo output
stage, frequency converter), lines between components and interference
suppressor filter, if the suppressor filter has not been placed at the component
directly.
Shield cables at both ends.
Unshielded wire ends of shielded cables should be as short as possible.
The entire shield must, in its entire perimeter, be drawn behind the isolation,
and then be clamped under an earthed strain relief with the greatest possible
surface area.
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