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5 web troubleshooting, 6 modbus troubleshooting, Web troubleshooting – Emerson MONITORING OpenComms User Manual

Page 33: Modbus troubleshooting

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NIC Setup and Testing

27

Then, select number 2 for Display/Modify Communities. Verify that

the IP Addresses listed are valid for your network. Verify that you are

typing in the correct community name when trying to access SNMP.

The community name is case sensitive.
Once this information is verified, reboot the card and try to access

SNMP again.

6.5

Web Troubleshooting

If the card does not serve up a web page, but the Service Terminal is

functioning, SNMP is functioning, and the card is connected to the

network (verified through ping), then reboot the card. In this case, the

web server has been lost and needs to be restarted.
If the card serves up a web page, but the web page only displays “Dis-

covering connected device…” verify that the card is connected to the

desired device. Verify that the link lights DS13 and DS8 are blinking

on and off. DS13 indicates that the card is receiving from the con-

nected device. DS8 indicates that the card is transmitting to the con-

nected device.
If neither of the link lights is blinking, check the connection between

TB1 and P3. TB1 is used to interface to the Environmental units and

to some UPS’s. P3 is used to interface with some UPS’s. If DS13 is

blinking and DS8 is not, this indicates a communication problem

between the card and the connected device.
When this occurs, replace the NIC card and retry connecting to the

Web. If the problem persists, change the card in the device that the

NIC card is trying to interface with. Try to reconnect to the Web.

6.6

Modbus Troubleshooting

If the card does not respond to Modbus requests, verify that DS7,

“repeater port receive” is flashing during a request. In proper commu-

nications DS12 will also be flashing indicating, “repeater port trans-

mit.”
Verify proper wiring on the EIA 485 network. OpenComms NIC cards

should observe a “plus to plus” and “minus to minus” daisy chain con-

figuration.
Also verify that the proper slave ID has been set in service terminal.

Refer to 3.2 - Service Terminal for initiating a service terminal ses-

sion.