Tweco 400 XT Ultra-Cut Plasma Cutting System - Manual (Page 166)

ULTRA-CUT 400 XT
A-5� APPENDIX Manual 0-5275
�. If all else fails disconnect the pilot wire from the back of the torch head. Insulate it well or keep it away from any metal,
it may have HF (high frequency) on it when you try to start. Try to start, if the 20� is gone now the torch head is shorted.
209 Not used. Reserved codes from the earlier product.
210–211 Output current, measured by the work lead current sensor, is too high (210) or too low (211).
These are warnings and do not shut down the process but may explain poor cut quality or poor parts life.
Individual inverter sections have their own current sensors and the work lead has a current sensor whose signal should equal
the sum of the individual inverter sections. Each section is set to output a certain current based on its ”demand” signal. If
the current differs from the total “demand”, sum of the individual demands, the individual sections are checked to determine
if their output is correct compared with their demand signals.
If the individual sections are correct but the work current sensor signal differs from the total demand by more than 1�% code
210 (too high) or 211 (too low) is displayed.
If an individual inverter section was found to be in error causing the total current to be wrong, a different code would be
displayed in the range of 212 to 223 depending on which section was at fault.
Possible causes for work current signal too high:
• HCT1 Work Current Sensor
• Relay PCB
• CCM
Possible cause for work current to low.
• All the above plus a short to chassis caused by:
o User installed equipment connect behind the current sensor that makes a connection to work or earth allowing
current flow to bypass work sensor.
o Inverter + output shorted to chassis.
Troubleshooting:
1. For current too low due to a short disconnect work lead from back of unit. Check for continuity to chassis, there should
be none. Inspect for incorrectly connected user equipment.
2. If no shorts were found or if fault was current signal too high see section on code 207 for detailed description of the
power and signal paths for the work lead current sensor.
3. In the section on code 207 for Relay PCB it describes measuring the work current sensor signal when there is no current.
The signal should be zero and we assume it is or else you should have gotten the 207 code. If the zero current signal
is correct but there is an error while cutting, measure the signal on the �0pin ribbon cable (Relay board J� to CCM J23)
pins 27 (-) & 2� (+). The signal voltage should equal the cutting current * 0.02��. For example for 100A (100*0.02��)
=2.��V.
• If this signal is correct the fault is the CCM
• If it’s not correct the error may be in the Relay board or sensor. Follow the instructions for code 207 to measure the
voltage to and signal from the current sensor at J1 on the Relay board. The signal voltage should equal the cutting
current * 0.0133. For example for 100A (100*0.0133) =1.33V. For �00A would be �00*0.013 3= 5.33V.
• If power and signal are correct Relay board is faulty. If not correct the HCT1 work current sensor is bad.
212-223 Incorrect output from an inverter section.
Work current high or low due to wrong output from one inverter section. Individual code indicates which section.
Causes may be:
• The named inverter section output connector, J102 A or B, is not plugged in or is damaged.
• Ribbon cable with bad connection, perhaps not fully locked in place at either the inverter or the CCM.
• Defective inverter section.