Epson EM07ZS1647F User Manual page 132

4. Troubleshooting (PROFIBUS DP)
♦ 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.
120
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.
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.
Fieldbus I/O Rev.6