Hardware FAQ

FAQ

Power Self-Check

1. Current is zero

Issue analysis: Under normal conditions, when power is connected and no operation is performed, current should be at least about 0.1 A, which is the minimum standby current for motors. If current is zero, wiring may be incorrect and no current flows in the circuit. Use the correct wiring layout as shown.

Self-check: Use a multimeter to verify whether the power output is 48V. Measure both output ports.

CAN Cable Self-Check

CAN cable open circuit

Use a multimeter continuity test as shown. If the meter does not beep, the CAN cable has an open circuit.

CAN cable short circuit

Use a multimeter continuity test. If the meter beeps when connected between CAN H and L, the CAN cable is short-circuited.

In most cases, whether the CAN cable is open or shorted, re-soldering can fix it.

Backplane Self-Check

A normal backplane is shown below. If any solder joints are missing, manually re-solder them.

Cable Self-Check

Use a multimeter to test cable continuity. Key points:

• ⚡️ Check whether power cable is shorted or open -> Go to CAN section
• ⏏️ Check whether CAN cable is shorted or open -> Go to CAN section

Robot Arm

1. No motors are detected on the entire arm

Issue analysis: Possible causes include:

1. ⚡️ Power issue
2. ⏏️ CAN cable issue
3. 🕹︎ Backplane issue
4. ⚟ Cable harness issue

Start by excluding easy-to-check causes first:

• Check power -> Go to Power section
• Check CAN cable -> Go to CAN section
• Check backplane -> Go to Backplane section

If power, CAN cable, and backplane are all normal, continue with deeper checks:

1. Disconnect all cables.
2. Use isolated power and CAN to connect a single motor.
3. Use check_motor_status script to read current motor status.

Motor wiring method is shown below.

If script can read status:

• ✅ Motor is normal
• ✅ Power is normal
• ✅ CAN cable is normal

Then the likely root cause is:

• ❌ Cable harness issue

For cable troubleshooting, see -> Go to Cable Issues

Note: A CAN short can disable communication on the whole arm because CAN is daisy-chained along the arm. A short on power lines can cause serious accidents (rare but critical).

If script cannot read status, continue testing:

• ⚙️ Test other motors and check if they can report status

If other motors can report status:

• ❌ This motor may be damaged.

If other motors also cannot report status:

• ❌ Likely still a power/CAN issue
• ❌ If power/CAN were already excluded, software issues are also possible, such as missing PCAN driver

2. Only some motors are not detected

If only one or several motors have issues, then:

• ✅ Power is likely normal
• ✅ CAN backbone is likely mostly normal

Possible causes:

• ❌ Motor damage
• ❌ Cable harness issue

Use isolated power and CAN again to test suspect motors.

Note: Plugging/unplugging cables without cutting power may burn motor interfaces. Motors usually have two interfaces; try the other one for verification.

If motor is normal, continue checking harness quality.

Note: For partial detection failure, a CAN open-circuit in a branch is likely. Power-line faults are less likely but should still be checked.