A PowerFlex 70 (Bulletin 20A) or PowerFlex 700 (Bulletin 20B) that trips shows "Faulted" in the LCD HIM status line with the fault number, the fault name and the time since the fault, and the status light flashes red (
Fault or alarm
From PF70 p. 77 and PF700 p. 83:
- A fault stops the drive. Type 1, auto-reset run: if [Auto Rstrt Tries] is above 0, the drive waits [Auto Rstrt Delay], tries to reset and, if the cause has gone, restarts; the PF70 text adds that a Stop aborts the restart. Type 2, non-resettable: normally needs drive or motor repair; it resets at power-up after the repair. Type 3, user configurable: enabled or disabled in 238 [Fault Config 1] (PF70 p. 57; PF700 p. 52).
- An alarm does not stop the drive, but the condition can if left untreated. Type 1 alarms can be disabled in [Alarm Config 1]; Type 2 alarms are always on. Alarms clear by themselves when the condition goes (PF70 p. 82; PF700 p. 90).
Alarm numbers are a separate list: alarm 2 is UnderVoltage, fault 2 is Auxiliary Input (PF70 pp. 82, 85; PF700 pp. 90, 93).
What the HIM and the LEDs show
| Display | Fault | Alarm |
|---|---|---|
| LCD HIM (both drives) | "Faulted", fault number, fault name, time since the fault; Esc gives the HIM back | Bell symbol; the alarm name only for Type 2 alarms |
| LED HIM (PowerFlex 70) | The fault code, for example F 5 | No indication |
Sources: PF70 p. 78; PF700 p. 85. The PowerFlex 70 Enhanced Control drive does not support the LED HIM (PF70 p. 13).
PowerFlex 700 STS indicator (PF700 p. 84):
| STS | Meaning |
|---|---|
| Green flashing / steady | Ready, not running / running; no fault |
| Yellow flashing, drive stopped | Start inhibit: check 214 [Start Inhibits] |
| Yellow flashing or steady, drive running | Type 1 alarm: check 211 [Drive Alarm 1] |
| Red flashing | Fault: check [Fault x Code] or the fault queue |
| Red steady | Non-resettable fault |
On AC-input PowerFlex 700 frames 5…10 the precharge board has its own red Fault LED: two flashes for a DC bus short, four for line sync failed or low line; it resets only after power is cycled (PF700 p. 85). The PowerFlex 70 manual has no LED table; its symptom table gives a flashing red status light for a faulted drive (PF70 p. 86).
Reading the fault queue
| Data | PowerFlex 70 | PowerFlex 700 |
|---|---|---|
| Fault codes, [Fault 1 Code] = most recent | 243, 245, 247, 249: four faults (p. 58) | 243 to 257, odd: eight faults (p. 52) |
| Time of each fault, hours since first power-up | 244 to 250, even (p. 58) | 244 to 258, even (p. 53) |
| Values at the last fault | 224 [Fault Frequency], 225 [Fault Amps], 226 [Fault Bus Volts], 227/228 [Status 1/2 @ Fault] (pp. 55–56) | 224 [Fault Speed], 225, 226, 227, 228 (p. 50) |
[Fault x Time] minus 242 [Power Up Marker] below zero means the fault happened before the latest power-up (PF70 p. 58; PF700 p. 53). On the LCD HIM: Diagnostics > Faults > "View Fault Queue" (PF70 p. 96; PF700 p. 104). Codes 49, 51 and 52 are markers in the queue (power-up, queue cleared, faults cleared), not faults (PF700 p. 86; marked Enhanced Control in the PF70 table, pp. 79–80).
Common fault codes
Type "1/3" = Type 1 that can be disabled in [Fault Config 1]; "—" = no type printed. Pages: PF70 / PF700.
| No. | Name | Type | What the manual says | What to check | Pages |
|---|---|---|---|---|---|
| 2 | Auxiliary Input | 1 | Auxiliary input interlock open | Remote wiring | 79 / 86 |
| 3 | Power Loss | 1/3 | DC bus below the power-loss trigger longer than 185 [Power Loss Time]; PF700: 85 % of nominal | Incoming AC: low voltage or interruptions | 81 / 88 |
| 4 | UnderVoltage | 1/3 | DC bus below minimum. PF70 Standard Control: 509 V DC (600 V input), 407 V DC (400/480 V), 204 V DC (200/240 V). PF700: 407 / 204 V DC | Incoming AC: low voltage or interruptions | 82 / 89 |
| 5 | OverVoltage | 1 | DC bus above maximum | High line or transients; regeneration: longer decel or dynamic brake | 81 / 88 |
| 7 | Motor Overload | 1/3 | Internal electronic overload trip | Load so current stays within [Motor NP FLA]; PF70 also P549 [Flux Braking %] if enabled | 80 / 87 |
| 8 | Heatsink OvrTemp | 1 | Above 100 % of [Drive Temp]; PF700 also below about -19 °C | Ambient, fan, excess load; PF700: space heaters when cold | 80 / 87 |
| 12 | HW OverCurrent | 1 | Output current above the hardware limit | Programming, load, DC boost, DC brake volts; PF70 also drive output and motor for shorts | 80 / 87 |
| 13 | Ground Fault | 1 | Path to earth above 25 % of drive rating | Motor and external wiring at the output terminals for a grounded condition | 80 / 87 |
| 15 | Load Loss | — | Torque current below [Load Loss Level] longer than [Load Loss Time]; PF70: Enhanced Control only | Motor-to-load connection; level and time | 80 / 87 |
| 17 | Input Phase Loss | — | DC bus ripple above a preset level; PF70: Enhanced Control only | Missing phase, blown fuse | 80 / 87 |
| 21 | Output PhaseLoss | — | PowerFlex 700 only: current lost or low in one or more phases | Drive and motor wiring, phase-to-phase continuity at the motor terminals, loose leads | — / 88 |
| 24 | Decel Inhibit | 3 | Drive not following the commanded decel (PF70: accel or decel) while limiting bus voltage | Input voltage, system grounding; disable bus regulation, add a dynamic brake resistor or extend decel | 79 / 86 |
| 33 | Auto Rstrt Tries | 3 | Auto reset and run failed for the set tries | Correct the cause, clear manually | 79 / 86 |
| 36 | SW OverCurrent | 1 | Above the 1 ms rating, typically 200…250 % of continuous | Load, DC boost, DC brake volts | 81 / 89 |
| 38–40 | Phase U / V / W to Grnd | — | Phase-to-ground fault between drive and motor | Drive-to-motor wiring, motor for a grounded phase; last step: replace drive | 81 / 88 |
| 41–43 | Phase UV / VW / UW Short | — | Excessive current between two outputs | Motor and output wiring for a short; last step: replace drive | 81 / 88 |
| 64 | Drive OverLoad | — | 110 % for 1 min or 150 % for 3 s exceeded | Reduce load or extend accel | 79 / 86 |
| 70 | Power Unit | — | Output transistors in the active region instead of desaturation | Damaged output transistors; replace drive | 81 / 88 |
| 81–85 (PF700: 81–86) | Port x DPI Loss | PF70 —, PF700 2 | DPI port stopped communicating, or a SCANport device on a drive running DPI at 500k baud | Port wiring, port expander, adapter, HIM connection, [Logic Mask] | 81 / 88 |
Port 6 (codes 76, 86) is PowerFlex 700 firmware 6.002 and later only (PF700 p. 90); the PF70 fault table lists 81…85 while its cross-reference lists 81…86 (PF70 pp. 81–82). Codes 71–75 (PF700: 71–76) Port x Adapter mean the communication card has a fault: read that device's event queue.
PowerFlex 700 only: 18 Hardware PTC, 20 TorqPrv Spd Band, 28 See Manual, 88/89 Software Fault, 92 Pulse In Loss, 109/110 NVS I/O, 121 I/O Comm Loss, 122 I/O Failure, 130/131 Hardware Fault (PF700 pp. 87–89). Code 111 differs: Enable Hardware on the PowerFlex 70 (Enhanced Control), Power Down Csum on the PowerFlex 700; the PowerFlex 70 has Power Down Csum at 112 (PF70 pp. 79, 81; PF700 p. 88). The PF70 manual no longer lists fault 21 (PF70 p. 5). Full lists: PF70 p. 82, PF700 p. 90.
Port DPI Loss after unplugging a HIM
- Adapter removed on purpose with its bit in 276 [Logic Mask] at 1: the fault occurs; set the bit to 0 (PF70 pp. 60, 81; PF700 pp. 56, 88).
- PowerFlex 700 default: remove the HIM only in Auto mode, with ALT then Enter ("Remove Op Intrfc"); in Manual mode, or as the only control device, removal faults the drive (PF700 p. 102). PowerFlex 70: "Remove" allows removal without a fault if the HIM is not the last controlling device and has no Manual control (PF70 p. 95).
- PowerFlex 700 firmware 9.001 and later can keep running: 173 [DPI Loss Action] = 1 "Hold OutFreq" or 2 "Goto Preset1", port bit 16…18 in 238 set to 0, bits 21…23 in 259 [Alarm Config 1] left at 1. The HIM must not be the only stop source (PF700 p. 103).
Checks, step by step
- Record before any reset: the fault queue, 224…228, firmware 029 [Control SW Ver] (PF70 p. 22; PF700 p. 22), the catalog number and the STS state.
- 3, 4, 17: watch the incoming AC line for low voltage and interruptions; for 17, a missing phase or blown fuse.
- 5 and 24: high line or transients; longer decel or a dynamic brake. For 24, reprogram 161 [Bus Reg Mode A] / 162 [Bus Reg Mode B] to remove "Adjust Freq", or disable bus regulation and add a dynamic brake; correct line instability or add an isolation transformer (PF70 p. 87; PF700 p. 95). Decel Inhibit is not instantaneous: tests show 2…12 seconds (PF70 p. 9; PF700 p. 12).
- 13: motor and external output wiring for a grounded condition. 38–40: drive-to-motor wiring, motor for a grounded phase. 41–43: motor and output wiring for a short.
- 12: programming, load, DC boost, DC brake volts; on the PowerFlex 70 also the output and motor for shorts. 70: check for damaged output transistors.
- 7, 8, 36, 64: load against [Motor NP FLA], accel time, ambient temperature and fan.
Clearing faults safely
Manually (PF70 p. 78; PF700 p. 85): press Esc, correct the cause, then press Stop, cycle power, set 240 [Fault Clear] to 1, or use "Clear Faults" in the HIM Diagnostics menu. 240 = 2 "Clr Flt Que" also empties the queue; with 241 [Fault Clear Mode] = 0 "Disabled" a fault reset from any source is blocked, except for codes that are cleared indirectly by other actions (PF70 p. 57; PF700 p. 52).
Automatically: 174 [Auto Rstrt Tries], 0…9, default 0; 175 [Auto Rstrt Delay], default 1.0 s (PF70 p. 45; PF700 p. 41). Only Type 1 faults reset this way; the manual warns against it in an inappropriate application. Auto-restart can start the motor without warning; follow the plant's permit and lockout rules. Before working on the drive, measure the DC bus at +DC and –DC: it must be zero (PF70 p. 8; PF700 p. 11).
When it is hardware
- 70, and 38–43 once wiring and motor are cleared: replace drive (PF70 p. 81; PF700 p. 88).
- 900–930 Fatal Faults, Type 2: cycle power, replace the Main Control Board, contact Rockwell Technical Support (PF70 p. 80; PF700 p. 86).
- 105 Pwr Brd Chksum2 that persists, and 108 Anlg Cal Chksum: replace drive (PF70 pp. 79, 81; PF700 pp. 86, 89).
- PowerFlex 700: 88/89, 109/110, 122, 130/131 point to the Main Control Board; 121 to the I/O board or Main Control Board (PF700 pp. 87, 89). 106 Incompat MCB-PB: load compatible firmware; frames 7…10 need 4.009 or later (PF700 p. 87). STS steady red: non-resettable fault (PF700 p. 84).
Planning the replacement
Each catalog number has an end-of-life page with Rockwell's lifecycle status. 20AC030A0AYNANC0 (PowerFlex 70) shows End of Life with a discontinuation date of 30/05/2027; 20BC030A0AYNADB0 (PowerFlex 700) shows Discontinued since 30/11/2023, both read on 3 November 2026. Both pages list the category Engineering Replacement with no catalog number, so the new drive is chosen by rating, enclosure and options. Other catalog numbers: end-of-life lookup. If the replacement is a PowerFlex 753/755, see PowerFlex 753/755 fault codes. Need an engineer on site: breakdown support.
Frequently asked questions
How do I tell a fault from an alarm on a PowerFlex 70 or 700?
A fault stops the drive and the LCD HIM shows "Faulted" with the fault number; an alarm leaves the drive running, shows a bell symbol and clears by itself (PF70 pp. 77–78; PF700 pp. 83, 85). On the PowerFlex 700 the STS light flashes red for a fault and yellow for a Type 1 alarm (PF700 p. 84).
What is fault 4 UnderVoltage on a PowerFlex 700?
The DC bus fell below 407 V DC on 400/480 V input or 204 V DC on 200/240 V input (PF700 p. 89). It is a Type 1 fault that can be disabled in [Fault Config 1]; check the incoming AC line for low voltage or interruptions.
What does fault 81 Port 1 DPI Loss mean?
DPI port 1 stopped communicating; codes 81 to 85 are ports 1 to 5 (PF70 pp. 81–82; PF700 pp. 88, 90). Check the port wiring and the HIM connection; if the adapter was removed on purpose, set its bit in 276 [Logic Mask] to 0.
How do I see the fault history on a PowerFlex 70 or 700?
Read [Fault 1 Code] (243), the most recent fault, and the following codes: four on the PowerFlex 70, eight on the PowerFlex 700 (PF70 p. 58; PF700 p. 52). On the LCD HIM: Diagnostics > Faults > "View Fault Queue" (PF70 p. 96; PF700 p. 104).
Sources
- Rockwell Automation,
20A-UM001P-EN-P , PowerFlex 70 Adjustable Frequency AC Drives User Manual (Standard Control firmware 2.xxx, Enhanced Control firmware 2.xxx…5.xxx), 02/2018 — chapter 2 "Troubleshooting" pp. 77–87; parameters pp. 22, 45, 47, 55–58, 60; pp. 5, 8–9, 13, 95–96 - Rockwell Automation,
20B-UM002H-EN-P , PowerFlex 700 AC Drives – Frames 0…10 User Manual (Vector Control firmware 4.001 and up), 12/2022 — chapter 2 "Troubleshooting" pp. 83–95; parameters pp. 22, 41, 43, 50, 52–53, 56; pp. 11–12, 102–104
Read 13 November 2026. This article paraphrases the sources and does not quote them; read the original documents before designing or working on a system. Links open the latest edition in Rockwell's literature library; page numbers refer to the edition cited.