Communication Interruptions; Terminating Resistors - ESAB Aristo Mig 3001i Service Manual

Starting sequence
On power-up, the board's CAN controller reads in the bus speed from the
micro processor: 400 kbit/s.
The circuit board displays the starting sequence from power-up.
LED1 lights red. Then LED1, LED2 and LED3 lights green.
When the board has been initiated, and the power source is in the application
program, LED1 flashes continously with a green light.
LEDs on circuit board 20AP1

Communication interruptions

If the CAN bus fails, the control panel will normally generate a fault message.
Check the following points in the event of problems with CAN communications:
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The terminating resistor. The CAN bus resistance must lie in the range
50-130 ohm: the optimum value is 60 ohm. To check the resistance, turn
off the power source and measure the resistance between pins I and J in
connector socket XS3.
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All screen connections must be sound. Measure the resistance between
the shell of the CAN connector connected to the MMC unit and the shell of
the most distant CAN connector on the CAN bus. There must be a short
circuit between those two end points.
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Good contact with the chassis connections from/to the control board and
suppressor capacitors. See the main circuit diagram.
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The connection cable between units. Check that the correct type of cable
is being used. Check that each signal is being carried by the correct core.
CAN H and CAN L must be carried by the twisted pair.

Terminating resistors

In order to avoid communication interference, the ends of the CAN bus must
be terminated by resistive loads.
Principle diagram of the CAN bus and connecting up of the terminating resistors
ca41_20_1 - 29 -
S0740 800 196/E101019/P76