Epson EM07ZS1647F User Manual page 137

♦ Causes of Error
Possible Cause
Disconnected
terminating resistors
Cable disconnection
Disconnected
connector
Disconnected signal
wire
Loose connector
Loose signal wire
Noise
(external cause)
Broken unit
No cause is
identified.
Fieldbus I/O Rev.6
Examination Method
(1) Check that terminating
resistors are connected to
both ends of the network.
(2) Measure resistance between
signal wires with device
power supply OFF.
→ Normal: 100 to 120 Ω
Measuring point: Connection
of the trouble unit
For detail, refer to the section
4.2.3.1 Connection Problem.
Check for the connection of
connectors and signal wires.
→ The connectors and signal
wires should be firmly
connected.
Checkpoint: all stations and all
branch taps
For details, refer to the section
4.2.3.2 Loose Connector and
Signal Wire.
Check the noise intrusion via the
following paths (1) to (3).
(1) Noise via shield
(2) Induced noise via
communication cable
(3) Device power supply
→ For details, refer to the section
4.2.3.3 Noise Intrusion.
Replace the trouble unit with a
new one.
→ Verify whether the problem is
fixed.
Identify the trouble point by
dividing the network.
→ For details, refer to the section
4.2.3.4 Broken Unit
Examination.
4. Troubleshooting (PROFIBUS DP)
Countermeasure
Fix the problem.
How to find the trouble
point:
Remove the terminating
resistor on one end of the
network. The trouble point
is where resistance
changes from 220 Ω .
Connect the connectors
and signal wires again.
Take countermeasures
against noise.
Replace the unit with a
new one.
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