ESAB 100i Service Manual page 83

108 Tip to Electrode Voltage Fault
The Pilot voltage, measured between tip and electrode varies with different current and gas type, flow rate and
consumable design.
Once the arc is transferred the pilot switch opens leaving the tip basically floating. The voltage then is deter-
mined by how much of a cold gas barrier surrounds the arc. Too much current or too little gas and the arc
starts to contact the tip reducing the voltage difference between tip and electrode and leading to a double arc
that destroys the consumables.
The CCM measures both electrode and tip voltage and calculates the difference. If the difference between tip
and electrode is found to be less than a minimum voltage we stop cutting and set a fault for the 108 code. The
normal tip to electrode voltage is different for different processes so the min value for each process is embedded
in the cut charts when using the Automatic Gas Control.
During piloting and ramping (the time from transfer until the current reaches full cut current), we lower the
allowed tip to electrode voltage to about 80% of that allowed during cutting because the current is lower and
the gas flow is lower during that time.
Causes for 108 code:
• Gas Flow/pressure too low for consumable parts being used.
o If gas source pressure is not well regulated it is possible pressure may be OK at times and drop too
low at other times such as during a cut.
o A leak of the preflow/plasma gas after the pressure/flow control (DPC) can reduce the pressure/flow
to the torch because some if it is bypassing the torch, while seeming to have enough pressure/flow at
the gas control.
• Cut current set too high for consumable parts being used.
• With Automatic Gas Control a faulty component would be expected to set a fault code in either the DPC
or GSC. However, if a wrong process is selected which doesn't match the consumable type or if using
a custom process where pressure has been set too low or current too high that could cause 108 without
setting any faults in the Automatic Gas Control.
• A broken pilot wire in the torch lead making intermittent contact can allow piloting or sometimes the
torch can transfer using only HF (high frequency). This intermittent connection will upset the tip voltage
measurement and can result in the 108 code. Symptom is - it may cut for a short time then fault. Check
for an open/broken torch lead pilot wire.
• Physically shorted torch body between anode (tip) and cathode (electrode).
The fault resulting in a 108 code is measured while cutting. It is more likely a shorted torch body, depending
on the resistance of the short, it will set code 208 (Unwanted Current) as that is measured prior to starting cut
However, it must be considered as a last resort.
109 Part Process not Configured.
This represents a status, not a fault. This is used with the Automatic Gas Control only. It means the operator
hasn't loaded the cutting process from the program embedded in the cutting table CNC controller. The solu-
tion is to load a process. The code will continue to be displayed until the CNC Start is applied at which time
the code will clear.
110 Device locked.
This means the DPC or GSC is still in the process of downloading a new cutting process. This should only occur
with the Automatic Gas Control if you apply CNC Start before the download process is finished.
Manual 0560956456
iSERIES 100 /200 /300 /400
APPENDIX A-63