Statusword Decoded: 0x6041 Bit-by-Bit Reference
May 04, 2026
The CiA 402 statusword is a 16-bit value at object 0x6041 that a servo drive reports to its master every bus cycle. It is the drive's self-description: which DS402 state it is in, whether voltage is present, whether it is warning or faulting, and — for op-mode-specific bits — whether the current setpoint has been reached or the following error threshold has been crossed.
TL;DR
Bits 0–3 of the statusword uniquely identify the DS402 state (Ready to Switch On, Switched On, Operation Enabled, Fault). A drive running happily on an EtherCAT bus typically reports 0x0237 — Operation Enabled with Voltage Enabled, Quick Stop not active, and Remote set. Bit 5 (Quick Stop) is active-low: 1 means "no quick stop", 0 means "quick stop commanded".
What the statusword is
The statusword is defined by IEC 61800-7-201 / CiA 402-2. It is a single 16-bit object (0x6041, sub-index 0, UNSIGNED16). The drive writes it; the master reads it and decides what to command next. Bit 3 (Fault) forces a state-machine jump regardless of what the master says; bit 9 (Remote) tells the master whether its controlwords are even being considered.
Bit-by-bit reference
| Bit | Label | Name | When it is 1 |
|---|---|---|---|
| 0 | RTSO | Ready to Switch On | In Ready to Switch On, Switched On, Operation Enabled, Quick Stop Active. |
| 1 | SO | Switched On | In Switched On, Operation Enabled, Quick Stop Active. |
| 2 | OE | Operation Enabled | Only in Operation Enabled and Quick Stop Active. |
| 3 | F | Fault | Drive is in Fault or Fault Reaction Active. |
| 4 | VE | Voltage Enabled | DC bus is present and OK. |
| 5 | QS | Quick Stop | Active-low. 1 = no quick stop. 0 = quick stop commanded. |
| 6 | SOD | Switch On Disabled | Only in Switch On Disabled. |
| 7 | W | Warning | Vendor-defined warning condition (no state change). |
| 8 | MS | Manufacturer | Often brake, motion active, motor-on. |
| 9 | RM | Remote | Fieldbus controlword is being processed. 0 = local/keypad control. |
| 10 | TR | Target Reached | PP/PV: setpoint reached. HM: at home. CS*: usually unused. |
| 11 | ILA | Internal Limit Active | Setpoint clamped by software position, torque, or velocity limit. |
| 12 | OMS | Op-mode specific | PP: Setpoint Ack. HM: Homing Attained. CS*: Drive follows command. |
| 13 | OMS | Op-mode specific | PP/CSP: Following Error. PV: Max Slippage. HM: Homing Error. |
| 14–15 | MS | Manufacturer | Vendor-defined. STO status, warning latched, homing subphase. |
State identification masks
You can decode the state by masking bits 0–6 of the statusword:
| State | Mask & value |
|---|---|
| Not Ready to Switch On | SW & 0x4F == 0x00 |
| Switch On Disabled | SW & 0x4F == 0x40 |
| Ready to Switch On | SW & 0x6F == 0x21 |
| Switched On | SW & 0x6F == 0x23 |
| Operation Enabled | SW & 0x6F == 0x27 |
| Quick Stop Active | SW & 0x6F == 0x07 |
| Fault Reaction Active | SW & 0x4F == 0x0F |
| Fault | SW & 0x4F == 0x08 |
Each of these is clickable in the statusword decoder — the state machine highlights on change.
Common decoded values
0x0250 — Switch On Disabled
Binary 0000 0010 0101 0000. Bits 4 (VE), 6 (SOD), 9 (RM) set. Drive is initialised, DC bus up, being controlled from the fieldbus, waiting for a Shutdown command. What you see right after power-up on a healthy drive.
0x0231 — Ready to Switch On
Binary 0000 0010 0011 0001. Bits 0 (RTSO), 4 (VE), 5 (QS-not-active), 9 (RM) set. Drive has accepted Shutdown. Output stage still off. Send Switch On next.
0x0233 — Switched On
Binary 0000 0010 0011 0011. Add bit 1 (SO). Output stage is closed, zero-current hold, motor ready.
0x0237 — Operation Enabled
Binary 0000 0010 0011 0111. Add bit 2 (OE). The drive is live and will follow motion commands per the op mode in 0x6060. This is the target state for any running system.
0x0218 — Fault (with DC bus up)
Binary 0000 0010 0001 1000. Bit 3 (F), bit 4 (VE), bit 9 (RM) set. Drive has latched a fault but the DC bus is still present. Read 0x603F for the error code, fix the cause, then pulse CW.7 to reset.
Mode-specific bits
Target Reached (bit 10)
Semantics differ per op mode: - PP: position within 0x6067 window for 0x6068 time. - PV: velocity within 0x606D window for 0x606E time. - HM: at home position and at standstill. - CSP / CSV / CST: often unused — cyclic modes never "arrive". Use bit 12 (Drive Follows Command) instead.
Internal Limit Active (bit 11)
A non-obvious source of "drive moves but never reaches target". ILA = 1 means a software limit (position, torque, velocity) is clamping the setpoint. Motion continues but Target Reached will not assert.
Following Error (bit 13, PP/CSP)
Hard threshold 0x6065 exceeded for 0x6066 time. Usually triggers Fault Reaction (per 0x605E) — you will see bit 13 briefly, then bit 3 assert as the drive transitions to Fault.
Manufacturer deviations
- Yaskawa Sigma-7: bit 8 = Brake Released, bit 14 = Tuning-less active, bit 15 = Homing subphase.
- Beckhoff EL72xx / AX8000: bit 14 = TxPDO toggle, bit 15 = warning latched. Bit 8 may signal Motion Active.
- Kollmorgen AKD: bits 14–15 commonly STO status and brake. Under TwinCAT NC, the NC layer adds its own faults that do not always appear in CiA bit 3.
- Siemens SINAMICS on PROFIdrive: you are reading ZSW1, not 0x6041. Bit meanings are entirely different (bit 0 = Ready to Switch On, bit 6 = Switch-On Inhibit, bit 4 = No OFF2). The controlword you would need to send to enter this state is in the controlword cookbook.
FAQ
What is the CiA 402 statusword? A 16-bit value at object 0x6041 that a CiA 402 drive reports to its master, encoding the DS402 state and mode-specific flags.
What does statusword 0x0237 mean? Operation Enabled with Voltage Enabled, Quick Stop not active, and Remote set. The drive is running and accepting motion commands.
Why is bit 5 Quick Stop inverted? The spec defines the bit as active-low so a disconnected master (CW = 0x0000) naturally commands a safe stop instead of running the drive.
What does Target Reached mean in cyclic modes? Usually nothing. Cyclic Sync modes consume setpoints every cycle and do not "arrive". Use bit 12 (Drive Follows Command Value) as the truthful tracking flag.
Can the statusword differ between EtherCAT and CANopen drives? No. The bit layout is identical per IEC 61800-7-201. Transport details differ; semantics do not.
Try it
Paste a captured value and see which bits are set, which DS402 state the drive is in, and — for the controlword your master would need to send to enter that state — see the controlword cookbook.