4. Troubleshooting (PROFIBUS DP)

♦ Causes of Error

Possible Cause

 

Examination Method

Countermeasure

{ Disconnected

(1)

Check that terminating

Fix the problem.

terminating resistors

 

resistors are connected to

 

{ Cable disconnection

 

both ends of the network.

How to find the trouble

{ Disconnected

(2)

Measure resistance

point:

connector

 

between signal wires with

Remove the terminating

{ Disconnected signal

 

device power supply OFF.

resistor on one end of the

wire

→ Normal: 100 to 120

network. The trouble point

 

z Measuring point: Connection

is where resistance changes

 

of the trouble unit

from 220 .

 

z For detail, refer to the section

 

 

4.2.3.1 Connection Problem.

 

{ Loose connector

Check for the connection of

Connect the connectors and

{ Loose signal wire

connectors and signal wires.

signal wires again.

 

→ 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.

 

{ Noise

Check the noise intrusion via

Take countermeasures

(external cause)

the following paths (1) to (3).

against noise.

 

(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.

 

{ Broken unit

Replace the trouble unit with a

Replace the unit with a new

 

new one.

one.

 

→ Verify whether the problem

 

 

is fixed.

 

z No cause is

Identify the trouble point by

 

identified.

dividing the network.

 

 

→ For details, refer to the

 

 

section 4.2.3.4 Broken Unit

 

 

Examination.

 

120

Fieldbus I/O Rev.6

Page 132
Image 132
Epson EM07ZS1647F manual Broken Unit Examination