Download Modicon M168 Controllers Network Connectivity

Troubleshooting and Diagnostics
B.1
General Troubleshooting
Troubleshooting Tasks
CPU Indicator Not Flashing
The network status (NS) indicator does not flash when the unit is not operating. This
could be because primary power has been lost or there has been another detected
internal dysfunction.
Confirm that you have configured the application for the correct protocol (BACnet
MS/TP or BACnet/IP) using the SoHVAC software. A BACnet IP module does not
operate when it is configured for BACnet MS/TP communications (and vice-versa).
Make sure that power is available and connected properly to the power terminals on
the controller. This can be done using a multimeter reading the voltage across the
positive and negative terminals.
Functioning Unit Does Not Respond
The unit is usually operational when the network status (NS) indicator flashes
normally. However, keep in mind that it will not respond if it detects an invalid
configuration parameter. The module starts only if the configuration settings are
valid.
Before you compile your application in SoHVAC, confirm that you have generated
the BACnet profile (see page 140) with the Tools → BMS Configuration →
Generate BACnet profile command.
RS-485 activity: RS-485 communications can be monitored by observing the status
of the TXD (transmit) and RXD (receive) LED indicators. During communications,
both LEDs should show activity.
Ethernet activity: A flashing Link/Activity LED indicates ongoing Ethernet
communications. You can use a sniffer program (such as Wireshark,
www.wireshark.org) to monitor Ethernet traffic to and from the module.
Inoperable Input or Output
If the network status (NS) indicator and other inputs and outputs are operating
properly, check the status of these items:
z The input or output is detected as damaged. In this case, contact a Schneider
Electric representative for assistance.
z The program that controls the inputs and outputs may not be correct (especially
if this is the first time you are using the controller). Check your program.
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S1A3839300 12/2012