Determining Argon hardware failure

If Argon (servo drive) refuses to operate in any meaningful way, it is good to perform few tests for the hardware to identify possible hardware failures.

Verifying AC to HV DC circuity

See Argon supply voltage troubleshooting

Testing power stage

Motor power stage and braking resistor output consists IGBT transistors that typically short circuit if they are damaged. Testing of such failure needs only a multimeter with resistance measurement function.

1. Unplug all connectors from the drive at least 30 minutes before testing as residue voltages may disturb this test and pose a danger. After 30 minutes fully disconnected, ensure that voltage has been safely discharged.
2. Measure resistance between J4 pin VN against BR,U,V and W. A typical resistance is between 100 kΩ - 10 MΩ. If resistance is less than 10 kΩ, there may be a failed IGBT.
3. Measure resistance between J4 pin VP against BR,U,V and W. A typical resistance is between 100 kΩ - 10 MΩ. If resistance is less than 10 kΩ, there may be a failed IGBT.

Testing regenerative drive transistor

Use this method to test regenerative drive transistor (which burn if regenerative resistor resistance is too low, or it has a wiring short circuit):

1. Measure resistance between BR and VN terminals when drive is off and all connectors have been unplugged. If resistance is below 10 kΩ, the regenerative drive transistor damaged.

SimpleMotion V2 port

Schematic diagram consisting RS485 receiver and few other components connected to Argon's J2 port

SimpleMotion V2 port (J2 on argon) is protected by clamping diode (type NXP PESD5V0S4UD) that is identified as D19 in the adapter and Argon drive. That diode typically burns if 24VDC is miswired in the port or if faulty Ethernet/RJ45 cable is being used. Same diode exists also in the SimpleMotion V2 USB adapter and may be damaged as well. Sometimes fault propagates longer and kills also RS485 driver chip (Texas Instruments SN65176BDR) which is identified as IC4 on Argon and IC1 on SM V2 USB Adapter.

Typical symptom of failure is inability to connect drive through SimpleMotion bus (i.e. Granity does not connect). Sometimes D19 short circuits 5V bus to ground making devices appear completely dead. To test if the device still has life, removing D19 (and possibly IC1 or IC4) can be used to verify whether lights come on when voltage is applied to the device.

The parts mentioned here on Argon and SMV2USB may be replaced by person capable of desoldering and soldering SMT components.

Testing the failure

Typically D19 short circuits to GND when it has been damaged. To test whether this is the case, measure resistance with multimeter between GND and RS485_A / RS485_B pins of RJ45 connector. If resistance is low (less than 10 Ohms), the D19 is shorted and should be replaced.

Replacing components to repair communication faulure

Typical hot air soldering station

Replacing surface mount components like D19 or IC4 are most conviently done with hot air soldering station.

Typical repair procedure

1. First eliminate the original wiring error to prevent same mistake again
2. Remove D19
3. Try drive communication (just 24V supplied and RJ45 wired straight to SMV2USB).
   1. If device works, solder a new D19 in place. Job done.
   2. If no luck, try with known-good or new SMV2USB as well.
   3. If still no connection is possible, replace also IC4, and try again.

If still no connection (after new D19, IC4 and SMV2USB), then failure might have propagated further making repair more challenging. Granite Devices may be still able to repair it cost efficiently.

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