6 Troubleshooting Guidelines In This Chapter. . . .

6 Troubleshooting Guidelines In This Chapter. . . .
Troubleshooting
Guidelines
In This Chapter. . . .
— Isolating a Communication Problem
— Troubleshooting Chart
— EBC Module Diagnostic LEDs
— Using NetEdit for Troubleshooting
— Diagnosing Network Cable Problems
6
6–2
Troubleshooting Guidelines
Isolating a Communication Problem
Troubleshooting
Guidelines
If you are experiencing a problem communicating with an EBC module, the problem
can usually be isolated to one of four components of the communication link:
• the EBC module itself (hardware or firmware)
• the communication program or the setup of the EBC module
• the cabling and connections
• other external influences, such as electrical noise, heavy communication
traffic on the network or exceeding the power budget
Diagnostic Tools
and Techniques
Several available tools and techniques can help you isolate a communication
problem:
• The LEDs on the face of the module indicate the status of the link, the
module, and the network communications.
• Replacing the module may determine whether the problem is in the
module.
• NetEdit3 displays a list of the active modules on the network and their
protocol and configuration settings.
• Cable testing devices can pinpoint short or open circuits or diagnose
attenuation problems and other cabling problems.
• Diagnostic tools within your PC-based Control software.
Troubleshooting Chart
The following chart summarizes the different types of communication failures you
could experience. In each case the power must be applied to the base, and you must
be attempting to communicate with the EBC in question.
The meaning of the diagnostic LEDs is explained begining on page 6-4.
Troubleshooting Chart
Legend:
Off
EBC Module LEDs
LINKGD
ACT
ERROR
OR
ÈÈ
Flash
Corrective Action
LINKGD
ACT
ERROR
ÈÈ
H2–EBC100
H2–EBC100
STATUS
LINKGD
ACTIVE
ERROR
STATUS
LINKGD
ACTIVE
ERROR
OR
On
ÈÈ
ÈÈ
Ethernet Base Controller Modules, 3rd Edition, 11/04
1. Cycle power to the base. This will clear
the ERROR if it was due to a transient
condition.
2. Replace EBC module
6–3
Troubleshooting Guidelines
ÈÈ
ÈÈ
Troubleshooting Chart (Continued)
Legend:
Off
EBC Module LEDs
H2–EBC100
STATUS
LINKGD
ACTIVE
ERROR
LINKGD
ACT
ERROR
On
Flash
Corrective Action
1. Try another cable that you know works.
Check pinouts (see page 2–8).
2. Try another port on the hub or
another hub.
3. Replace EBC module.
2. Try another port on the hub or another
hub.
H2–EBC100
STATUS
LINKGD
ACTIVE
ERROR
LINKGD
ACT
ERROR
3. Make sure you have not exceeded the
recommended cable length for your
network cable. The link signal could
arrive with sufficient strength even
though the data transmission does not.
4. Could be related to Windows configuration. Consult Windows documentation.
Note: This is also the indication of proper
operation! Troubleshoot only if you are
failing to exchange data.
ÈÈ
ÈÈ
LINKGD
ACT
ERROR
1. Try another cable between PC and hub
or EBC and hub.
OR
H2–EBC100
ÈÈ
STATUS
LINKGD
ACTIVE
ERROR
LINKGD
ACT
ERROR
2. Try another port on the hub or another
hub.
3. Look for errors in the setup of the EBC
module.
H2–EBC100
OR
STATUS
LINKGD
ACTIVE
ERROR
Ethernet Base Controller Modules, 3rd Edition, 11/04
Troubleshooting
Guidelines
1. Try another cable between PC and hub.
6–4
Troubleshooting Guidelines
EBC Module Diagnostic LEDs
EBC LEDs
The EBC module has three indicator lights which show the status of the following:
• signal path between the EBC and the hub
• signal between a PC and an EBC
• EBC module hardware
Troubleshooting
Guidelines
H2–EBC and H2–EBC–F
H4–EBC(–F)
LINKGD
ACT
ERROR
LINK GOOD
Indicator
LINK GOOD
ERROR
ACTIVITY
The green LINKGD (LINK GOOD) LED is on steady when the EBC module is
connected properly to an active device on the network and is receiving 5VDC
operating voltage from the PLC power supply. The LINKGD LED verifies that the
proper cables are connected, and the EBC module is functioning correctly. If a
mismatch with the 10BaseT or 10BaseFL connections occurs this LED will not be
illuminated.
ACTIVITY Indicator The red ACT (ACTIVITY) LED flashes to indicate that the module is detecting data
on the network. If any network device is sending or receiving data, the ACT LED will
be illuminated. In idle mode (no network traffic) this LED is OFF. During heavy
communication loads this LED will be on steady.
ERROR Indicator
If the EBC module’s red ERROR indicator is flashing or on steady, a fatal error has
occurred. The error may be in the EBC module itself, or a network problem may be
causing this symptom. The ERROR indication can be caused by a faulty ground, an
electrical spike or other types of electrical disturbances. Cycle power to the system
to attempt clearing the error.
Ethernet Base Controller Modules, 3rd Edition, 11/04
6–5
Troubleshooting Guidelines
H2–EBC100
STATUS
LINKGD
ACTIVE
ERROR
100MBIT
TXD
RXD
The green STATUS LED is on steady when the EBC module is receiving 5VDC
operating voltage from the PLC power supply and self diagnostics indicates the
module is functioning properly.
LINK GOOD
Indicator
The green LINKGD (LINK GOOD) LED is on steady when the EBC module is
connected properly to an active device on the network and is receiving 5VDC
operating voltage from the PLC power supply. The LINKGD LED verifies that the
proper cables are connected, and the EBC module is functioning correctly. If a
mismatch with the 10BaseT or 10BaseFL connections occurs this LED will not be
illuminated.
ACTIVITY Indicator The green ACT (ACTIVITY) LED flashes to indicate that the module is detecting
data on the network. If any network device is sending or receiving data, the ACT LED
will be illuminated. In idle mode (no network traffic) this LED is OFF. During heavy
communication loads this LED will be on steady.
ERROR Indicator
If the EBC module’s red ERROR indicator is flashing or on steady, a fatal error has
occurred. The error may be in the EBC module itself, or a network problem may be
causing this symptom. The ERROR indication can be caused by a faulty ground, an
electrical spike or other types of electrical disturbances. Cycle power to the system
to attempt clearing the error.
100MBIT
Indicator
The green 100M (100MB) LED is on steady when Ethernet data is detected at
100BaseT frequency.
Serial TXD
Indicator
The green TXD (Serial TXD) LED flashes when the EBC’s serial port is transmitting
data.
Serial RXD
Indicator
The green RXD (Serial RXD) LED flashes when the EBC’s serial port is receiving
data.
Ethernet Base Controller Modules, 3rd Edition, 11/04
Troubleshooting
Guidelines
STATUS
Indicator
6–6
Troubleshooting Guidelines
Using NetEdit3 for Troubleshooting
Troubleshooting
Guidelines
NetEdit3 is a software utility which came with this manual. To review the procedures
for running and using NetEdit3, see Chapter 3. NetEdit3 allows you to:
• See active modules on the network.
• Examine and change the modules’ configuration settings.
• See the firmware revision number.
• Review statistical information about communication errors by type.
You can also use your PC’s DOS “Ping” command to verify communications with a
network server. The PC’s NIC must have the TCP/IP protocol enabled and the
server must have a valid IP address. Visit www.microsoft.com for inforamtion on the
“Ping” command.
Select a Module
The Module box shows the Ethernet
Addresses of all modules which are
currently linked to the NetEdit3 utility. If your
EBC module is not on this list, try the
following:
•
Change Protocol selection and click on
Query
Network.
See
Change
Protocol on the next page.
•
Confirm that your PC has IPX or
TCP/IP protocol loaded.
•
Confirm that the EBC module’s Link
Good LED is on.
NOTE: The Ethernet Address (MAC) is permanently assigned at the factory, and it is
printed on a label on the side of the EBC module. See page 3–13 if you need help
locating the label.
Module Info>
General
Information
When the Module Info tab is selected, the General Info box lists the
selected module’s Firmware Revision, Booter Revision, DIP Switch
Setting, PWB Revision, PLD Revision and CPU Revision.
This box is in the lower left section of the NetEdit3 screen.
Ethernet Base Controller Modules, 3rd Edition, 11/04
6–7
Troubleshooting Guidelines
Change Protocol
Ethernet Stats
•
•
•
•
•
•
Missed Frames – frames lost
due to unavailability of buffer
space.
TX Collisions – detected when
RXD+ and RXD– become active during a data transmission. Two
devices are trying to communicate at the same time.
Lost Packets – packets that overflow the queue.
Bad Packets – packets that fit the Ethernet standard but are not in the
right format for the EBC module.
Unknown Type – a foreign command was received and could not be
interpreted. This will probably happen only during software driver
development.
Send Errors – the Ethernet standard number of retries were attempted
for a transmission.
Replacing the EBC If you are replacing an existing EBC module with a new one, you need to set up the
new module with the same Module ID as the module you are replacing. If you used
Module
the DIP switch to set the Module ID, you will need to set the DIP switch on the
replacement module to the same Module ID. See page 2–3 or 2–4 to review the
procedure for setting the Module ID using the DIP switch.
If you set up your original EBC module using NetEdit3, you will need to duplicate the
settings in the new module using the same procedures. See page 3–5 through 3–12
to review the procedures for using NetEdit3.
If you set up your original EBC module using your PC-based Control software, you
will need to refer to the appropriate documentation.
WARNING: Your system can be damaged if you install or remove system
components before disconnecting the system power. To minimize the risk of
equipment damage, electrical shock, or personal injury, always disconnect the
system power before installing or removing any system component.
Ethernet Base Controller Modules, 3rd Edition, 11/04
Troubleshooting
Guidelines
If you are experiencing a problem
communicating from your PC to a module
that does not appear on the list of active
modules, try changing the protocol and
clicking on Scan Network. You may be able
to link to your module with the other protocol.
If you are not sure which protocol driver is loaded on your PC, refer to page 3–4, as
well as your Windows documentation.
If you are able to see the problem module on
the list of modules currently active on the
network, you can select the module to see
the Ethernet Stats for that module. Select
the module by clicking on the Ethernet
Address in the Module box.
To begin a new statistical record, click the
Clear Stats button.
The diagnostic information available in the
Ethernet Stats box is:
6–8
Troubleshooting Guidelines
Troubleshooting
Guidelines
Diagnosing Network Cable Problems
If you are experiencing communication problems, swapping cables is one of the
simplest diagnostic procedures you can perform. If the network operates correctly
with a different cable, you have isolated and cured the problem. If possible, use a
short run of cable to test the network because problems with longer cable runs can
be more difficult to diagnose and are more often intermittent.
If you are unable to swap cables, verify the proper operation of all other network
components. You probably have a cable problem if you have verified that your:
• EBC module is working correctly.
• EBC module configuration is correct.
• RLL program or PC program is correct.
• hubs are working correctly.
• Windows configuration is correct.
• network adapter card is the correct type, and it is working correctly.
It is a good maintenance practice to test network cables periodically and maintain a
permanent record of cable characteristics. A number of cable test instruments are
available to test 10/100BaseT and 10BaseFL networks. These instruments will
check the electrical or optical characteristics of your cabling, including:
• Continuity – This is a check to make sure the communication pairs are
wired correctly, and that the wires are continuous from end to end. In the
case of fiber optic network this is a test to be sure light is transmitted
from one end of the cable to the other.
• Attenuation – This refers to the amount of signal loss over the cable
segment at the signal frequency of interest. The 10/100BaseT
specification allows for a maximum signal loss of 11.5 decibels (dB) for
the entire link at the signal frequency used by 10/100Mbps Ethernet.
The 10BaseFL specification calls for the optical loss in link segment to
be no greater than 12.5 dB.
• Crosstalk – Crosstalk occurs when a signal in one pair of wires is
electromagnetically coupled to an adjacent pair. This is critical
for10BaseT networks which are susceptible to noise interference.
10BaseFL networks are virtually immune to noise interference.
NOTE: Any significant difference between the cable characteristics of the
transmitter and receiver can cause communication errors.
Ethernet devices continually monitor the “receive data” path for activity as a means
of verifying their link is working correctly. When the network is idle, each network
device (including the EBC module) sends a periodic link test signal to verify that the
network is working. If the link test signal or other network activity is not received
periodically, the Link Good LED on the EBC module is turned off.
Ethernet Base Controller Modules, 3rd Edition, 11/04
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