Epson RC700 Manual page 220

4. Troubleshooting (DeviceNet)
♦ Causes of Error
Possible Cause
 Master unit
configuration
 Disconnected
terminating
resistors
 Cable
disconnection
 Disconnected
connector
 Disconnected
signal wire
 Loose connector
 Loose signal
wire
 Voltage drop of
communications
power supply
 Noise
(external cause)
 Broken unit
 No cause is
identified.
210
Examination Method
(1) Start applicomIO Console
application and check that the
configuration has no difference
with the network condition.
(2) Check that the configuration data
were written in flash.
(3) Check that the network load is
within allowable range.
 For details, refer to the section
4.1.3.6 EPSON RC+ Master
Configuration.
(1) Check that terminating resistors
are connected to both ends of the
network.
(2) Measure resistance between signal
wires with communications power
supply OFF.
→ Normal: 50 to 70Ω
 Measuring point: Connection of the
trouble unit
 For details, refer to the section
4.1.3.1 Connection Problem.
Check for the connection of connectors
and signal wires.
→ The connectors and signal wires
should be firmly connected.
 Checkpoint: all nodes and all branch
taps
 For details, refer to the section
4.1.3.2 Loose Connector and Signal
Wire.
Measure voltage of communications
power supply at the unit with a trouble.
→ Normal: 11V or more between V+
and V-
 If the voltage is 11 to 14 V, the unit
is a possible cause. Fix the problem
on the unit.
Check the noise intrusion via the
following paths (1) to (3).
(1) Noise via DRAIN (FG)
(2) Induced noise via communication
cable
(3) Communications power supply
→ For details, refer to the section
4.1.3.3 Noise Intrusion.
Replace the broken 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
4.1.3.4 Broken Unit Examination.
RC700 / RC90 Option Fieldbus I/O Rev.12
Countermeasure
Change the configuration.
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 120 Ω.
Connect the connectors
and signal wires again.
Check the voltage of the
power supply.
Calculate the current
capacity of the cable and
add more communications
power supplies.
Take countermeasures
against noise.
Replace the unit with a
new one.