YOKOGAWA FA-M3V e-RT3 Plus, Hardware Manual

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A3-21
IM 34M06C11-01E
 Protecting Special Modules against Noise
- Analog and communication modules are designed to handle low-level or high-speed
signals. Place the lines of these signals at a distance of more than 10cm away from
other I/O signal lines and route them through separate cable ducts.
- It is especially difficult to distinguish analog signals and noise and this will cause
errors when an analog signal overlapped by noise is converted into a digital signal.
As a precaution, lay the analog signal cables away from noise sources such that
noise overlapping will not happen and insert a filter (such as a filter circuit, a filter or
software calculation filter) to attenuate noise.
- Always use specified cables only and be especially careful about the way they are
routed for grounding and interconnection. For further details, see the instruction
manual of each module.
 Protecting I/O Signals against Noise
- Segregate the AC I/O signal lines from DC I/O signal lines when routing them. If
this is not feasible, use collectively shielded lines for each group of these signal
lines.
- Segregate signal lines carrying larger current from other signal lines when routing
them. If this is not feasible, use shielded lines for signal lines carrying large current.
- If any inductive load is to be connected to an input or output terminal of the FA-M3,
install a surge protector or a diode near the load. For further details, see “Inductive
Load Countermeasures,” in subsection A3.6.4, “Connecting Input Devices” or
“Inductive Load Countermeasures,” in subsection A3.6.5, “Connecting Output
Devices.”
Note
Install a protective device, such as a surge arrester, when the FA-M3 is to be used in a
district with a high frequency of thunder.