Epson EM07ZS1647F User Manual

Page 132

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

Ω

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.

120

Fieldbus I/O Rev.6