Tweco 100 Ultra-Cut Plasma Cutting System with Automated Gas Control - Manual (Page 177)

ULTRA-CUT 100 XT
Manual 0-5303 APPENDIX A-53
Troubleshooting Pilot Board problems.
1. The Pilot board is behind the CCM in the AC 300 XT and all Ultra-Cut XTs or on the upper section of the
second inverter module in an AC 200 XT and has two LEDs. The first one, D11, a green LED, indicates the
board has bias power and should be on all the time when the unit is turned on. The second LED, D2, also
green, is on when the pilot is enabled, that is the pilot IGBT switch is turned on. The pilot is enabled near
the end of preflow time and remains on until the transfer is established or for 15 seconds after which a 102
code is displayed. If D2 performs as expected you know the CCM, Relay board and work current sensor
are not causing the problem.
2. If D11 on the Pilot board is not on check if the 10 pin ribbon cable is connected between the Pilot board (J42)
and the Relay board (J3). Measure for 24 VDC on the Pilot ribbon cable test connector pin 2 (+) and pin 10
(-). If 24V is present and neither D11 nor D2 lights then the Pilot board may be defective. Pilot board end
of the ribbon cable could also be the cause.
What should happen on the Relay board is LEDs D12, work Current Detected & D11, Pilot Current Detected
should both be off. When you apply START after 2 seconds (Preflow time) D7, Pilot Enable, should come
on. Also D23, RF ON, should come on indicating the Arc Starter is being enabled. Normally D23 would only
be on for a moment until pilot current is detected. Then D11 would be on (and D23 off) until arc transfer or
pilot timeout (15 sec.) Since a pilot has not been detected D11 should not come on.
3. If the work current sensor is defective it could be telling the relay board (and thus the CCM) that there is
already a transferred arc so no need for pilot. D12, a green LED on the Relay board, is on if work current
is detected. If D12 is not on skip to step 5, otherwise disconnect J1, the work sensor connector. If D12 is
still on the Relay board is defective.
4. If D12 goes out when J1 is disconnected, plug it back in and measure voltage from TP1 (common) to J1-1,
should be positive 12-15VDC. Now measure J1-2, should be negative 12-15VDC. Now measure J1-3,
should be 0 +/- 0.05V. If any of these are wrong disconnect J1 and measure again (on the relay board, not
the harness). If still wrong the relay board is defective. Otherwise it’s the work sensor.
5. Pilot Enable signal comes from the CCM on pin 15 of the 40 pin ribbon cable between the Relay board
(J4) and the CCM (J23). It should be low, less than 2V relative to TP1 on either the CCM I/O board or the
Relay board. You can also measure this on TP11 of the I/O board. If the signal does not go low when the
pilot should be enabled at the end of preflow time then the CCM is probably defective. You can also jumper
TP11 on the CCM I/O board to TP1, also on the I/O, to see if that will light D7, the Pilot Enable LED, on the
Relay board. If it does, that further confirms the CCM is bad. If jumping TP11 to TP1 does not light D7 on
the Relay board, the problem is likely the Relay board or possibly the ribbon cable.
103 Lost Pilot
Code 103 occurs when Pilot has ignited as sensed by the pilot current sensor on the Pilot board , but went out
on its own while CNC Start is still active before the pilot timeout (�5 ms. or 3 sec.).
Possible causes:
• Preflow gas pressure too high, for manual gas controls check cut charts for proper setting. For DFC 3000
check that the process is correct for the consumables.
• Cutting current set too low for the torch parts being used. Pilot current level is automatically set based on
the cutting current. A low cutting current results in a lower pilot current that may not be able to sustain
a pilot for higher current torch parts.
• Remote Analog Current Control switches set wrong can also result in lower than normal pilot current
setting. See section on these switch settings under next section for code 10�.
• Broken torch pilot wire.
• Defective Inverter module puts out less current than it’s set for.