PID Repairing Guide

PID stands for Potential Induced Degradation. Solis inverters may display "PID Repairing" on the screen when first turned on or during operation. This issue is typically related to the DSP (Digital Signal Processor) and occurs if the DSP firmware is missing or corrupted, or if the DSP board is faulty or not connected properly.

Causes of the "PID Repairing" Fault

The following are common reasons for the "PID Repairing" alarm:

• Vented inverter: Firmware upgrades may not resolve the issue.
• Corrupted DSP: Attempt a firmware upgrade first; if unsuccessful, the DSP board may need replacement.
• No AC voltage on site: Restore AC power to resolve.
• Power outage: An outage can trigger this; try upgrading the firmware.
• Lightning strike on site: Attempt a firmware upgrade; if it fails, the DSP board may need replacement.
• Blown fuses on RSDs (Rapid Shutdown Devices): Check and replace fuses as needed.
• 3-Phase Units: Requires a minimum of 195 Vdc on the DC inputs. If this is not met, the fault may persist.

Troubleshooting and Solutions

Initial Checks

1. Verify DSP Board Connection: Ensure the DSP board is seated properly—fully pushed in with all ribbon cables securely connected and not loose. If the board was loose, reconnect it and check if the inverter exits "PID Repairing" before proceeding.
2. Check AC Voltage: Confirm AC voltage is present at the site.
3. Inspect RSD Fuses: Replace any blown fuses if applicable.
4. 3-Phase Units: Verify the DC inputs have at least 195 Vdc, as this is a system requirement for proper operation.

DSP Firmware Update Process

If the initial checks don’t resolve the issue, update the DSP firmware:

1. Prepare the Solis Update Tool: Load a USB flash drive with the latest DSP firmware files (refer to the Current Firmware Version Master List) and insert it into the Solis Update Tool.
2. Connect the Tool: Plug the tool into the inverter and ensure the DC switch is ON.
3. Access the Menu: Press and hold the Enter button for 20-30 seconds until the main menu appears.
4. Navigate to Advanced Settings: Press Up once to highlight "Advanced Settings", then press Enter.
5. Enter the Password: Press Down, Down, Up, Enter.
6. Select DSP Update: Press Up until "DSP Update" is highlighted, then press Enter.
7. Check Current Version: Note the "Current Version" displayed. If it shows "00", the DSP firmware is likely missing or corrupted. For inverters with both "master" and "slave" DSPs, check both versions.
8. Start the Update:
   • Press Enter on the inverter.
   • Short-press the button on the update stick.
   • The red and green lights on the stick should flash; the green light will slow down as the update progresses.
9. Monitor Progress: If the inverter reverts to "PID Repairing" during the process, press and hold Enter again for 20-30 seconds to resume.
10. Verify Update: Once the lights stop flashing, check the "DSP Current Version" again. It should match the downloaded firmware version.
    • If it still shows "00" or the update fails repeatedly, the DSP board may be faulty.

Post-Update Steps

11. Power Cycle the Inverter: If the update doesn’t resolve the issue:
    • Turn the inverter completely off (AC and DC) and wait for the screen to go blank.
    • Turn it back on—AC first, then DC—and check if "PID Repairing" persists.
12. 3-Phase Units Voltage Check: If the fault remains on a 3-phase unit, confirm the DC inputs have at least 195 Vdc.

Next Steps

13. Contact Support: If the firmware update fails, the version remains "00", or the issue persists despite meeting voltage requirements (for 3-phase units), contact Solis Support. A DSP board replacement may be necessary.