Epson EM07ZS1647F User Manual

Page 137

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4. Troubleshooting (PROFIBUS DP)

♦ Causes of Error

Possible Cause

Examination Method

Countermeasure

{ Disconnected

terminating resistors

{ Cable disconnection
{ Disconnected

connector

{ Disconnected signal

wire

(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

z Measuring point: Connection

of the trouble unit

z For detail, refer to the section

4.2.3.1 Connection Problem.

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.

{ Loose connector
{ Loose signal wire

Check for the connection of
connectors and signal wires.
→ The connectors and signal

wires should be firmly
connected.

z Checkpoint: all stations and all

branch taps

z For details, refer to the section

4.2.3.2 Loose Connector and
Signal Wire
.

Connect the connectors
and signal wires again.

{ Noise

(external cause)

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.

Take countermeasures
against noise.

{ Broken unit

Replace the trouble unit with a
new one.
→ Verify whether the problem is

fixed.

Replace the unit with a
new one.

z No cause is

identified.

Identify the trouble point by
dividing the network.
→ For details, refer to the section

4.2.3.4 Broken Unit
Examination
.

Fieldbus I/O Rev.6

125

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