Manual

127
DeviceNet Gateway
10.2.4 Troubleshooting for DeviceNet Communication
If you encountered a problem with DeviceNet, check the operating condition and remove the cause
by referring to the table below. The monitor LEDs illuminate in two different colors (red/green). The
statues of these indicators can be used to check the DeviceNet status.
If an error occurs, the MS or NS LED will illuminate or blink in red. If you find a blinking or steady red
LED, check the connections of power-supply and communication cables and also check (reset) the
baud-rate and node-address setting switches once again, and then reconnect the power.
: Steady light, : Unlit, X: Blinking
Monitor LEDs
MS NS
Green Red Green Red
Status Countermeasure
{
-
{
- Normal
{
-
z z
Waiting for the node
address duplication
check to be completed by
the master
 Check if the baud rate of the master matches the baud rates of all
slaves. If any inappropriate setting is found, make the necessary
correction and then restart the system.
 Check if the connectors are properly engaged.
 Check if the communication power (24 VDC) is supplied. *1
 Check if the master is operating correctly.
 Check the communication cables for disconnection. *1
{
-

- Waiting for connection to
be established with the
master
 Check if the master is operating correctly.
 Check if the slave is registered in the scan list of the master.
-
{ z z
Hardware error  Contact IAI. (The DeviceNet board may have to be replaced.)
-

z z
DIP switch setting error
 Check if the baud rate of the slave matches the baud rate of the
master.
 Check if all items are configured correctly.
 If any inappropriate setting is found, make the necessary correction
and then restart the system.
{
- -
{
Detection of duplicate
node addresses or “bus
off” (halting of
communication due to
frequent data errors)
 Correct the node address(es) and then restart the system.
 Check if the baud rate of the slave matches the baud rate of the
master.
 Check if the communication cable length is appropriate. *1
 Check the communication cables for disconnection or loose or
disconnected connector. *1
 Check if the terminal resistors are installed correctly. *1
 Check for possible effect of noise, such as presence of noise
sources nearby or power lines running in parallel with the
communication cables. *1, *2
 If any inappropriate setting is found, make the necessary correction
and then restart the system.
{
- -

Communication time out
 Check if the baud rate of the slave matches the baud rate of the
master.
 Check if the communication cable length is appropriate. *1
 Check the communication cables for disconnection or loose or
disconnected connector. *1
 Check if the terminal resistors are installed correctly. *1
 Check for possible effect of noise, such as presence of noise
sources nearby or power lines running in parallel with the
communication cables. *1, *2
 If any inappropriate setting is found, make the necessary correction
and then restart the system.
The NS LED alternates between
steady green and blinking
green, or the NS LED alternates
between blinking red and
blinking green.
Communication error  Check if the slave is registered in the scan list of the master.
 Check the I/O areas for duplicate assignment to other slave.
 Check the I/O areas for overflow beyond the areas permitted by the
master unit (in the case of fixed assignment).
*1 A problem is suspected in the DeviceNet communication cable or DeviceNet power supply. Check
4.1, “Overall Wiring Configuration.”