Code dv4: Inversion Prevention Detection
Issue Description & Safety Warning
The Yaskawa A1000 AC Drive has triggered a critical Inversion Prevention Detection alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.
Official Troubleshooting Steps
Code type: Fault Manual section: Yaskawa A1000 Troubleshooting The Z pulse offset is not set properly to E5-11. - Set the value for Δθ to E5-11 as specified on the motor nameplate. - If the problem continues after cycling power, then replace either the PG option card or the PG encoder itself. Replacing the PG encoder or changing the application so that the motor rotates in reverse instead requires readjustment of the Z-pulse offset. (T2-01 = 3) Electrical signal interference along the PG cable affecting the A or B pulse. - Make sure the motor is rotating in the correct direction. - Look for any problems on the load side that might be causing the motor to rotate in the opposite direction. PG encoder is disconnected, not wired properly, or the PG option card or PG itself is damaged. - Rewire the PG encoder and make sure all lines including shielded line are properly connected. - If the problem continues after cycling power, then replace either the PG option card or the PG encoder itself.
Source: Yaskawa AC Drive A1000 High Performance Vector Control Drive Technical Manual (SIEP C710616 21H)
Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.
About Yaskawa A1000 AC Drive Alarms
Yaskawa controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code dv4 on the A1000 AC Drive identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Yaskawa's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.
Complete Alarm List: 280 Yaskawa A1000 AC Drive codes.
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