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Troubleshooting Section 7-2
Causes and Remedies for Other Types of Errors
Trouble Adding a Slave to the Network
Error Probable cause
After the MS indicator turns green, the NS indi-
cator doesn’t flash green - it turns red immedi-
ately.
Restart the faulty Slave Unit after checking the following points.
• Make sure that the Master and Slaves baud rate settings all match. If
they don’t match, set all of the baud rates to the same value.
• Check for a node number duplication. If necessary change the node
number settings so that each node has a unique number.
• See the troubleshooting steps below under the error heading:
“The NS indicator lights green but turns red after a short time.”
• If a particular Slave’s NS indicator is always red, replace that Slave.
The NS indicator lights green but turns red after
a short time
or
The NS indicator lights green but starts flashing
red after a short time.
Restart the faulty Slave Unit after checking the following points.
• Make sure that there are121-Ω terminators connected at both ends of
the trunk line. Connect 121-Ω terminators if the wrong resistance is
being used.
• Check whether all of the Slaves’ settings are correct.
• Check whether the communications cables are wired correctly.
• Check whether the power supply is set correctly.
• Check all the nodes for broken wires in the communications and
power supply cables attached to the connectors.
• Check whether power is correctly supplied to the network.
• If there is nearby equipment that generates electrical noise, take
steps to shield the Master, Slaves, and communications cables from
the noise.
• If an error has occurred with OMRON’s Master Unit, refer to the
DeviceNet Operation Manual (W267). If an error has occurred in a
Master Unit supplied by another maker, refer to the relevant user’s
manual.
• If a particular Slave’s NS indicator is always red, replace that Slave.
Error Probable cause
The NS indicator remains OFF. • Check if the baud rate of the Master Unit coincides with that of the
Slave Unit. If the baud rates are different, correct the baud rate of the
Slave Unit.
• Check that the Slave’s connector is connected correctly.
• Check whether the communications power supply is supplying
24 VDC.
• Make sure that the Master is operating properly.
When using an OMRON Master, refer to the DeviceNet Operation
Manual (W267).
When using another company’s Master Unit, refer to that Master’s
user’s manual.
• Check whether the communications cables are wired correctly.
• Check whether the power supply is set correctly.
• Check for broken wires in the communications and power supply
cables attached to the connectors.
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