Epson RC700, Manual

Page: 309 / 340

4. Troubleshooting (PROFIBUS DP)
RC700 / RC90 Option Fieldbus I/O Rev.14 297
♦
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

Measuring point: Connection
of the trouble unit

For details, 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.

Checkpoint: all stations and all
branch taps

For details, refer to the section
4.2.3.2 Loose Connector and
Signal Wire .
Connect the connectors and
signal wires again.

Electrical surges of
device power
supply
Measure voltage of the device
power supply at the trouble unit.
→ It should be within the range
of sufficient voltage for device
operation.
Check voltage of the device
power supply.

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.

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 .