Tweco 400 Ultra-Cut(May 2014) - Manual (Page 214)

ULTRA-CUT 100 XT/200 XT/300 XT/400 XT
A-86 APPENDIX Manual 0-5302
Troubleshooting:
1. GCM 1000XT (also called a Basic Gas Control) does not use CANBUS (fiber-optic) communication. A jumper in the gas
control connector J56 pins 8 & 9, gives the signal “Basic ID” telling the CCM not to expect any CANBUS. If somewhere
this circuit is open, in the Gas Control cable, connector pins, connection from the rear panel GCM connector, J55, to the
CCM (J26) CCM will expect to see a CANBUS connection and report this error because there is no CANBUS connected.
2. DFC 3000. If the gas control does not have power it will not communicate. Check for power to the gas control boards.
a. When using Auto Gas (DFC3000) with DMC & DPC if there is no power to the DMC main board, the green power
light on the DMC front panel will not be lighted. The main board receives several voltages from its separate power
supply board. For communication it needs +5VDC. There is a green LED, D17 (first on the left of the row of LEDs.)
that lights when the main board has +5V power.
b. The DMC power supply board has several blue LEDs that light when it has power. If none of these are on check for
the control cable being connected or the circuit breaker, CB2, on the plasma supply rear panel may be tripped in which
case there is probably a short somewhere.
c. The DMC power supply which supplies several voltages could be missing one or more and still have some blue LEDs
lighted. Check for voltages.
3. GCM 2010.
4. CANBUS / Fiber-optic communication errors can be difficult to troubleshoot, especially when they are intermittent. See
“Test the Fiber” below. Things to look for are:
a. The connectors not locked in place at either end of the fiber.
b. The fiber is damaged or bent sharply. This should not be the case if the fiber is inside the protective hose and the
hose properly secured in the strain relief but that is not always the case.
c. Dirt on the ends of the fiber or in the receiver/transmitter where the fiber plugs in. Blow out gently with clean dry air
such as is used to clean a camera lens.
d. Excessive electrical interference. While the fiber is immune to EMI it can bother circuits at either end. Check that all
the grounding connections are connected per the manual and are clean and tight. Check the resistance of the ground
rod (with all wires disconnected from it). It may have increased due to dryer weather conditions. See the instructions
in the Plasma Installation manual.
e. Defective receiver/transmitter or other circuits on either CCM or Gas Control main board. Otherwise replace either
(or both) Gas Control main board or CCM.
Transmitter / Receiver Tests. The transmitter/receiver pair on the PCB and the fiber cable looks like this:
Art # 12314
Test the fiber:
Note that the fiber goes from black on one end to blue on the other. Shine a bright light into one end and you should be able
to see light from the other end. This tells you the light is getting through but doesn’t prove it is strong enough.
The CCM is the communication master. It transmits then expects a reply from the Gas Control Module (GCM). The GCM
does not transmit on its own, only in response to a request from the CCM.
The black end of the fiber cable is inserted into the transmitter which is the gray housing on the PCB. The other end of the
transmitting fiber is blue and goes into the receiver with the black housing.
A few seconds after power is turned on and when the pump has started up the CCM will try to transmit continuously for a
while. You can unplug the fiber from the CCM and should see the transmitter red LED on the CCM PCB blinking. It may stop
after a while so recycle power before deciding it isn’t working. If no light, check one of the other transmitter/receiver pairs.
If none of them blink the problem is in the CCM.