Troubleshooting
6-8
Part 1128350_02
E 2020 Nordson Corporation
About Nordnet
Nordnet is a serial expansion network (or bus) that includes power, data, and
automatic termination. It is implemented as a master-slave architecture. The
LVC is the master and all other devices are slaves. The most common slaves
are temperature controls, but Nordnet can support many other types of
devicesaswell.
At power up, all slave modules are off (unpowered). Then the first module is
powered up, identified and initialized. Next, the LVC enables the next
attached module and performs the same steps working its way down the bus
one module at a time. By this method, all attached Nordnet modules are
discovered and put into operation.
Once operating, the master gives commands and the slaves respond with
the request ed action and/or data.
Troubleshooting Nordnet
SeeFigure6-1forthelocationoftheboards.
1. Check the Nordnet cables that are routed from board to board, starting at
the LVC master.
2. Observe the transmit/receive LEDs for the Nordnet master on the LVC
board. Typically, both LEDs flash to indicate data transfer on the bus.
3. Observe the LEDs on each board. In operation, all Nordnet nodes should
have power. If you watch immediately after applying power, you should
see each board power up in turn. Note that there is an order or sequence
to the bus.
4. One technique that should only be needed rarely is to add slaves to the
bus one-at-a-time. You must power the unit off when connecting or
disconnecting slaves. Do not connect or disconnect Nordnet with DC
power applied.
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