Comtrol Modbus Server - Manual (Page 38)

38 - Troubleshooting and Technical Support DeviceMaster Modbus Server User Guide: 2000535 Rev. C
General Troubleshooting
• If the device has a power switch, turn the device’s power switch off and on,
while watching the LED diagnostics.
• If the DeviceMaster does not have a power switch, disconnect and reconnect
the power cord.
• Verify that the network IP address, subnet mask, and gateway is correct and
appropriate for the network. If IP addressing is being used, the system should
be able to ping the DeviceMaster.
• Verify that the IP address programmed into the DeviceMaster matches the
unique reserved IP configured address assigned by the system administrator.
• If using DHCP, the host system needs to provide the subnet mask and
gateway.
• Reboot the system and the DeviceMaster.
• If you have a spare DeviceMaster, try replacing the device.
General Troubleshooting
This table illustrates some general troubleshooting tips.
Note: Make sure that you have reviewed the <hyperlink-
CrossReference>Troubleshooting Checklist on Page 37.
General Condition Explanation/Action
PWR or Status LED
flashing
Indicates that boot program has not downloaded to the
unit.
1. Reboot the system.
2. Make sure that you have downloaded the most
current firmware for your protocol:
fttp://ftp.comtrol.com/html/up_main.htm .
Note: If the PWR or Status LED is still flashing,
contact Technical Support.
PWR or Status LED not
lit Indicates that power has not been applied or there is a
hardware failure. Contact Technical Support.
Cannot ping the device
through Ethernet hub
Isolate the DeviceMaster from the network. Connect
the device directly to the NIC in the host system (see
Page 37).
Cannot ping or connect
to the DeviceMaster The default IP address is often not accessible due to the
subnet masking from another network unless 192.168 is
used in the network.
In most cases, it will be necessary to program in an
address that conforms to your network.
DeviceMaster
continuously reboots
when connected to some
Ethernet switches or
routers Invalid IP information may also cause the switch or
router to check for a gateway address. Lack of a
gateway address is a common cause.