Pepperl+Fuchs FieldConnex HD2-DM-A Manual page 89

H D 2 - D M - A / D M - A M
Type
Precision
Measuring Range
Default value
Definition:
Noise is an undesired disturbance within the signal frequency band.
Noise may appear with different characteristics. A high noise level may
cause communication problems and a lack of operational reliability.
•
B
Figure 9.1: Communication noise
A
B
Causes
Noise can be caused by many elements including:
• bad wiring practice
• bad shielding/grounding practice
• a non-regulated supply can pass supply voltage glitches onto
the bus
• a DC power supply injecting noise into the bus
• a regulated FOUNDATION Fieldbus supply injecting switching
noise into the bus
Segment or Field Device Jitter
Monitors the current maximum jitter of all active devices attached to the
segment. H1 jitter level is a value derived from the device jitter values.
Due to noise levels caused by additional affects the HD2-DM-A/DM-AM
indicates a first warning at 75 % (2.4 µs) of the maximum allowable jitter
level. This is an empiric value which can be modified for your special re-
Subject to reasonable modifications due to technical advances.
Pepperl+Fuchs Group • Tel.: Germany +49 621 776-0 • USA +1 330 4253555 • Singapore +65 67799091 • Internet http://www.pepperl-fuchs.com
U
A
Noise level
Signal level
Measured Values / Parameters
Value
10 mV
100 Hz ... 140 kHz
100 mV
t
Copyright Pepperl+Fuchs, Printed in Germany
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