Operating Instructions PA-xxP
961-00035 rev11
41/42
If the timing of the external signals (weld trigger inputs) is too fast, then the
welder will stop operating. All of the external fault signals are energised, and no
inputs are recognised. The welder will start sounding its beeper on and off. To
recover, power cycle the unit, and check the timing of the external PLC signals.
Warning
If these aspects have been considered, then the following checklist should be worked
through. The PAxxP offers several fault-reporting methods that are designed to assist in
fault diagnosis.
Check / Symptom
Reasons
Remedy
Is the status indicator
illuminated?
This LED illuminates to show the
machine is ON and that the internal
+24VDC supply is functioning.
No mains power.
Disconnect ALL external connections.
(It is quite common for external
wiring faults to cause the
+24VDC supply to be
overloaded).
Check mains fuse.
Check mains supply to machine.
Is the LCD illuminated?
The machine display will illuminate
ONLY if the +24V internal supply is
good.
Check mains supply to machine.
Check mains fuse.
Machine displays ‘Main
Transistor Bank Over
Temperature’.
The machine output will be inhibited if
the machine overheats.
Cooling of the
main transistors is achieved by an
internal heatsink and cooling fan which
“pulls” air through the heatsink, blowing
warm air out of the rear panel. In the
event that the heatsink reaches 70
C,
the drive to the transistors is inhibited
and all the fault signals on the remote
control socket are active. The
temperature must fall to 50
C before
welding can continue.
Clear any faults and the inhibit setting.
Allow machine to cool down and
investigate reasons for over heating.
Check output connections.
Check that the cooling air is able to
circulate and that the fan is not
obstructed.
Machine will not start
an arc.
Check that the arc gap is correct.
Normally this should be 0.8 mm to 1.2
mm in air. If the gap is too great then the
arc will not establish. If shielding gas is
used the arc distance, can be increased
as this lowers the arc voltage
requirement for welding.
Check the electrode material used as
this can affect the ease with which the
arc can initiate.
Check arc gap.
Check correct electrode material.
No RS232
communication.
Problems generally occur with incorrect
wiring or incompatible software or Baud
rate settings.
Check connections, particularly Tx &
Rx.
Verify the PC and the PAxxP are set to
the same Baud rate, and are using the
same protocols.
Ensure ‘logging’ option is set to ON, on
the configuration screen.
Machine continually
exceeds upper or lower
limits.
Often caused by variations in electrode,
particularly when new, or variations in
arc gap.
Run several trial welds and check
electrode alignment and arc gap.
Machine will not trigger
Most often caused by loss of +24VDC or
faulty trigger wiring, external PLC IO
timing.
Check wiring for the trigger signal.
Check PLC timing, refer note on page
32.
DO NOT REMOVE THE MACHINE COVER. THERE ARE NO USER
SERVICEABLE PARTS INSIDE.
Warning