Edwards, nEXT Turbomolecular Pumps, nEXT240, nEXT300 and ...

B800-00-880 Issue B
Maintenance
No Serial Comms
Table 25 - Fault finding (continued)
Symptom Check Action
Is the pump making a constant high
pitched noise?
Check that the electrical supply is
on, that the serial link is connected
and that the serial enable line is
active
If so, the rotor is out of balance.
Contact your supplier or Edwards.
Check slide switch is in the correct
position for RS232 or RS485
communication.
Left for RS485
Right for RS232
Right for parallel control and
monitoring
Fail signal or standby signal not
working
Check baud rate and if operating in
multidrop mode the node address
matches those of the pump.
Check that the red light is not on or
flashing
Check the serial enable line is
inactive
If LED is on, perform the checks
against the red alarm LED symptoms
Must be disconnected or driven high
for use of standby and fail lines
Yellow service LED is flashing a
repeated sequence
The red alarm LED is on
The red alarm LED is flashing
Check slide switch is in the correct
position for the RS232 or RS485
communication.
Normal during the software upgrade
process.
At other times indicates a problem
has been detected in the FLASH
memory
Note the position of the long flashes
within the series of 6 flashes to work
out the error code.
Left for RS485
Right for RS232
Right for parallel control and
monitoring
See flashing service codes in
Section 5.5.1
If during software upgrade then
complete the upgrade process.
Otherwise cycle power and if this
does not help then perform a
software upgrade.
Look up the flashing error code in
Section 5.5.1 and follow the advice
given.
Any other problems Contact your supplier or Edwards Contact your supplier or Edwards.
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