Emergency: same day
For a line-down motor, where the fault and parts allow. WhatsApp us before you send it so the bench is kept free.
Yaskawa · Yaskawa ABC C-channel
Yaskawa C-channel encoder repair
Yaskawa ABC C-channel is a Quadrature incremental with C channel encoder with 8,192, 16,384 or 32,768 counts per turn. We test it, repair or replace it and align it to the rotor. Found on: Yaskawa and Allen-Bradley servo motors. Star Automations is an independent multi-brand repair company and is not an OEM service centre.
- 25+years of servo repair, since 2000
- 3,000+customers across India
- 100+servo brands covered by our universal servo motor test equipment
- 5sites: Puducherry, Chennai, Bengaluru, Hyderabad, Delhi
- Same dayemergency repair option*
*Where the fault and parts allow. Every repaired unit returns with a printed test report.
Repair turnaround you can plan around
Send a photo of the nameplate first. We confirm whether the motor is repairable, and the quote, the same working day.
Urgent: 3 working days
Repair, encoder alignment and test, counted from the day the motor reaches the bench and the quote is approved.
Standard: 7 working days
Full repair, encoder alignment, run test under load and a printed test report.
- Free repairability check from a nameplate photo
- Printed test report with every motor
- Written warranty, terms stated on every quotation
- Pickup can be arranged; parts that must be imported are quoted with their own timeline
01Facts
Yaskawa ABC C-channel at a glance
| Device | Yaskawa ABC C-channel |
|---|---|
| Brand family | Yaskawa |
| Type and format | Quadrature incremental with C channel |
| Counts | 8,192, 16,384 or 32,768 counts per turn |
| Found on | Yaskawa and Allen-Bradley servo motors |
| Connector | Per motor model |
| Pole setting for alignment | Set at alignment |
C-channel encoders carry A, B and C lines. The C line steps through a V, W, Z, U sequence as the count advances, which the drive uses for start-up commutation.
02Faults
How Yaskawa ABC C-channel encoders usually fail
- Missing or weak A, B or Z channel
- Signal level outside range
- Dirty or damaged disc
- Commutation lines that no longer match the rotor
- Illegal commutation states after a power cycle
02+Alarms
Yaskawa ABC C-channel alarms and error codes: what they mean and what to check
These are the alarms most often seen with the Yaskawa ABC C-channel feedback device, with what each usually means and what to check first. Many encoder alarms are caused by the cable, connector or battery, not the encoder, so the checks below can save a repair.
| Alarm | Usually means | Check first |
|---|---|---|
| A.C1 | Servo runaway: the motor turns away from the command, often a wrong phase or encoder alignment | Check the encoder and motor phase wiring; encoder alignment |
| A.C2 | Phase detection error: the commutation signals are invalid | Encoder alignment and the cable |
| A.C3 | Phase A or B line disconnected | Cable and connector, then the encoder |
| A.C4 | Phase C (index) line disconnected | Cable and connector, then the encoder |
| A.d0 | Position error overflow | Can follow lost encoder counts; check the encoder signal, then the mechanics and gains |
Alarm numbers differ slightly between Sigma generations and Allen-Bradley drives. Alarm numbers and wording change with drive series and firmware, so check the manual for your drive. Drive brand names are used only to identify alarm lists. Star Automations is an independent multi-brand repair company and is not an OEM service centre.
Typical causes and checks
- Alarm at every power-up: reseat the connector at both ends, check the encoder supply at the motor end, and look for a broken wire.
- Alarm only when the axis moves or the cable flexes: suspect a break inside the cable chain, or a shield that has come loose.
- Alarm after coolant, washdown or rain: look for moisture or corrosion in the connector and behind the encoder cover.
- Alarm at random with other drives running: check earthing and shield clamps, and keep the feedback cable away from power cables.
- Alarm after a motor, encoder or drive change: check the type, the motor data in the drive, and the encoder alignment.
Encoder, cable or drive?
Swap in a known-good feedback cable first. If the alarm stays, move the motor to another axis if the drives are the same type. If the alarm follows the motor, the encoder or motor needs testing. If it stays on the axis with a good motor and cable, the drive needs testing. We test the encoder, the motor and the drive, so send the nameplate if you are not sure which it is.
Related guides: Yaskawa A.810 alarm, Yaskawa A.C90 alarm, Servo encoder alarms.
03Process
How the repair is done
Receive and identify
We read the nameplate and encoder label and confirm the exact type.
Test
Count per turn, data status, alarm flags and, where fitted, incremental lines are checked on the bench.
Repair or replace
Board, connector or sensor faults are repaired; a matched encoder is fitted where repair is not sensible.
Align
Commutation is set to the rotor and checked at every pole pair using the electrical angle.
Verify and report
The motor is run on the bench and the readings are recorded in the report.
See encoder alignment, memory programming and replacement.
04Related
Other Yaskawa encoders we repair
05FAQ
Questions
What do encoder alarms on a Yaskawa ABC C-channel usually mean?
Most fall into four groups: no communication, corrupted data, a fault reported by the encoder itself, and a position or commutation mismatch. The alarm table on this page lists the common codes and the first check for each.
How can I tell whether the Yaskawa ABC C-channel encoder, the cable or the drive is at fault?
Swap in a known-good feedback cable, then move the motor to another axis if possible. If the alarm follows the motor, the encoder needs testing; if it stays on the axis, the drive does. A cable or battery fault can be fixed without sending anything.
Can you repair a Yaskawa ABC C-channel encoder?
Yes. We test the position count and status, repair or replace the encoder, align it to the rotor and run the motor. We repair Yaskawa units; Star Automations is an independent multi-brand repair company and is not an OEM service centre.
What counts does it give?
8,192, 16,384 or 32,768 counts per turn depending on the type.
How is the C channel checked?
We power-cycle the encoder in each commutation state and look for illegal states.
What should I send for a Yaskawa ABC C-channel enquiry?
A clear photo of the motor nameplate and, if the cover is off, the encoder label. You can send the motor or only the encoder.
06Enquiry
Send the nameplate or encoder label
A clear photo of the motor nameplate and, if the cover is off, the encoder label is enough to start. We reply with whether it can be repaired and a quote.
Message received
Our team replies by email or WhatsApp, usually the same working day. For a line-down motor, WhatsApp +91 97866 22233.
→How it works
From nameplate photo to a tested motor in 7 steps
One route for servo motors, encoders and drives. You see the price before any work starts, and the report before the unit leaves our bench.
- 1 · Nameplate photoSend it on WhatsApp or the form
- 2 · Repairable? QuoteUsually the same working day
- 3 · Courier or pickupThe unit reaches our bench
- 4 · Bench diagnosisInsulation, windings, brake, encoder
- 5 · RepairFailed parts, bearings, seals, brake
- 6 · Align and run-testEncoder aligned; no-load and load run
- 7 · Report and dispatchPrinted test report with the unit
- Line down?Servo Swap ships a tested unit first. How Servo Swap works
EmergencySame day*
Urgent3 working days
Standard7 working days
*Where the fault and parts allow. Turnaround counts from when the unit reaches our bench and the quote is approved.