Tweco 300 XT Auto-Cut 400V - Manual (Page 152)

AUTO-CUT 300 XT
A-70 APPENDIX Manual 0-5290
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.