The short answer
Yaskawa and Mitsubishi servos are close on performance: both publish 26-bit encoders and a 3.5 kHz speed response for their current lines, Sigma-X and MR-J5. The difference is ecosystem and upkeep. Yaskawa fits EtherCAT and MECHATROLINK machines, and Mitsubishi fits CC-Link IE TSN and SSCNET III/H lines with battery-less absolute encoders as standard. Allen-Bradley Kinetix 5700 is the natural pick when the PLC is a Rockwell Logix controller, because axes, tuning, safety and faults all live in Studio 5000 Logix Designer.
- Sigma-X: 26-bit encoder, 3.5 kHz speed response, MECHATROLINK-4/III, EtherCAT or analog/pulse. Sigma-7 encoders are 24-bit.
- MR-J5: 26-bit battery-less absolute encoder. The amplifiers support CC-Link IE TSN, SSCNET III/H and a general-purpose interface, and the MR-J5-G-N1 adds EtherCAT.
- Kinetix 5700: Integrated Motion on EtherNet/IP. Load observer and adaptive tuning (tuningless) are on by default with firmware 13.001+ and Logix Designer v33+.
- Alarm styles differ: Yaskawa A.C90, Mitsubishi AL. 016.1, Kinetix FLT S45 – FDBK COMM FL.
| Point | Yaskawa Sigma-7 / Sigma-X | Mitsubishi MR-J5 | Allen-Bradley Kinetix 5700 |
|---|---|---|---|
| Motion networks | Sigma-X: MECHATROLINK-4/III, EtherCAT, analog/pulse. Sigma-7: MECHATROLINK-III, EtherCAT | CC-Link IE TSN (-G), SSCNET III/H (-B), general-purpose (-A), EtherCAT (-G-N1) | EtherNet/IP Integrated Motion |
| Encoder resolution | Sigma-X 26-bit; Sigma-7 24-bit | 26-bit | Depends on motor feedback (Hiperface DSL, Hiperface, EnDat supported) |
| Absolute encoder backup | Battery on Sigma-7 absolute encoders (A.830 battery alarm, A.810 backup alarm) | Battery-less on MR-J5 motors (manufacturer statement) | Feedback-dependent; FLT M05/M06 cover battery-backed feedback |
| Auto-tuning | Tuning-less function, autotuning with or without host reference, custom tuning (Sigma-7) | One-touch tuning, adaptive tuning, quick tuning | Load observer and adaptive tuning (tuningless) on by default |
| Safety | Hard Wire Base Block (HWBB); Sigma-7 EtherCAT with FSoE variant listed | STO and SS1 stop methods; safety over EtherCAT on -G-N1 | STO; Timed SS1 (-ERS3 series B+); Monitored SS1, SS2, SOS, SLS, SLP, SDI with GuardLogix (-ERS4) |
| PLC ecosystem fit | Any EtherCAT master; Yaskawa and MECHATROLINK controllers | Mitsubishi iQ-R/iQ-F and motion controllers; EtherCAT masters via -G-N1 | ControlLogix, CompactLogix, GuardLogix |
| Alarm display style | A.xxx code on drive panel and SigmaWin+ (for example A.C90) | AL. xxx.x with detail number (for example AL. 016.1) | LCD fault text (for example FLT S54 – POSN ERROR) and Logix fault log |
| Set-up software | SigmaWin+ | MR Configurator2 | Studio 5000 Logix Designer |
The options side by side
1Yaskawa Sigma-7 / Sigma-X
Best for: EtherCAT or MECHATROLINK machines, OEMs that ship to many PLC brands, and wide motor ranges.
Sigma-X is Yaskawa’s current line. Its launch release states a 26-bit encoder, a 3.5 kHz speed response frequency and 7,000 min⁻¹ maximum speed, and 400 V SERVOPACKs from 500 W to 15 kW arrived in 2025. Sigma-7 remains common in the field. Its manual documents a tuning-less function, autotuning and custom tuning, and the full A.xxx alarm list with reset rules.
- Network-neutral via EtherCAT
- Tuning-less mode for quick start-up
- Clear alarm table (stop group and resettable yes/no)
- Sigma-7 absolute encoders need a battery; replace it with control power on
- Check Sigma-X variant availability for your voltage and network
Maker’s page: Yaskawa
2Mitsubishi MELSERVO-J5 (MR-J5)
Best for: Mitsubishi PLC/motion lines and sites that want to stop changing encoder batteries.
Mitsubishi states that MR-J5 motors have 26-bit battery-less absolute encoders. The amplifiers come in CC-Link IE TSN, SSCNET III/H, general-purpose and EtherCAT (-G-N1) versions. The troubleshooting manual (SH(NA)-030312ENG-P) gives every alarm a detail number with a cause-and-check table, and it lists one-touch and adaptive tuning as the remedies for resonance-related alarms.
- Battery-less absolute encoder as standard
- Detail numbers point to the exact sub-cause
- Quick tuning (about 0.3 s per Mitsubishi’s EtherCAT listing)
- Pick the right network suffix at order time
- A battery-less motor swap raises AL. 025.1 and needs re-homing
Maker’s page: Mitsubishi Electric
3Allen-Bradley Kinetix 5700 (and 5500)
Best for: Rockwell Logix plants, especially where integrated safety over EtherNet/IP is wanted.
Kinetix 5700 is a shared-bus, multi-axis system on EtherNet/IP. With -ERS4 drives and a GuardLogix 5580 or Compact GuardLogix 5380, it adds Monitored SS1, SS2, SOS, SLS, SLP and SDI. Load observer and adaptive tuning run by default on current firmware. Kinetix 5500 covers smaller axes and works with CompactLogix 5370 controllers.
- Single software for logic, motion, safety and diagnostics
- Readable fault text on the drive
- Integrated safety catalogue
- Little benefit outside a Logix architecture
- Fault descriptions sit in a separate reference (2198-RD003) and online lookup tool
Maker’s page: Rockwell Automation
Which one fits your plant
- Choose Kinetix 5700 or 5500 if the PLC is ControlLogix, CompactLogix or GuardLogix. Integrated Motion and integrated safety outweigh any spec-sheet difference.
- Choose MR-J5 if the line runs Mitsubishi iQ-R or iQ-F with CC-Link IE TSN or SSCNET III/H, or if battery-less absolute encoders are a priority.
- Choose Sigma-X or Sigma-7 for EtherCAT or MECHATROLINK machines, or for an OEM that ships to customers with different PLC brands.
- On a generic EtherCAT master, Yaskawa and Mitsubishi (-G-N1) are both credible. Decide on local support, spares and which alarm style your technicians already know.
Tuning: how each one gets to a stable axis
All three now aim to make an axis stable without manual gain work. Yaskawa’s Sigma-7 manual describes a tuning-less function, plus autotuning with or without a host reference and custom tuning for when the defaults are not enough. Mitsubishi’s MR-J5 manual names one-touch tuning and adaptive tuning as the fixes for resonance, and Mitsubishi’s EtherCAT listing claims quick tuning in about 0.3 s. Rockwell enables load observer and adaptive tuning by default on -ERS3 series B and -ERS4 drives (firmware 13.001, Logix Designer v33). Further tuning is covered in the Motion System Tuning Application Technique, MOTION-AT005.
Tuning features cannot fix a poor inertia match or a loose coupling. Check the load-to-motor inertia ratio before blaming the drive.
Diagnostics: what a technician sees
For a technician, the biggest daily difference is how each brand reports a fault. The same physical fault, a lost encoder signal, shows up three ways:
| Fault | Yaskawa Sigma-7 | Mitsubishi MR-J5 | Kinetix 5700 |
|---|---|---|---|
| Encoder communication lost | A.C90 Encoder Communications Error | AL. 020 Encoder normal communication error 1 (AL. 016 at power-up) | FLT S45 – FDBK COMM FL |
| Position error too large | A.d00 Position Deviation Overflow | AL. 052 Excessive error | FLT S54 – POSN ERROR |
| Absolute position lost / battery | A.810 Encoder Backup Alarm; A.830 Encoder Battery Alarm | AL. 025 Absolute position erased; AL. 09F Battery warning | FLT M05 – FDBK BATTERY LOSS; FLT M06 – FDBK BATTERY LOW |
See the cross-brand alarm guide for the full equivalence table and the first checks for each alarm family.
How we compared them
We compared the current flagship general-purpose line from each maker: Yaskawa Sigma-X (with Sigma-7, which most sites still run), Mitsubishi MR-J5 and Rockwell Kinetix 5700 (with 5500 for smaller axes). Facts come from each maker’s manual or product page, read on 26 October 2026: the Sigma-7 product manual SIEP S800002 19O, the MR-J5 troubleshooting manual SH(NA)-030312ENG-P, and the Kinetix 5700 user manual 2198-UM002Q. We have not bench-tested the drives. Where a maker does not publish a figure (for example a single encoder resolution for Kinetix, which depends on the motor), we say so.
Frequently asked questions
Is Yaskawa better than Mitsubishi for servos?
On published numbers they are level: both state 26-bit encoders and a 3.5 kHz speed response for Sigma-X and MR-J5. Mitsubishi states that its MR-J5 encoders are battery-less, and Yaskawa offers more network choices, including MECHATROLINK. The better choice is the one that matches your controller and the support you can get locally.
Can a Kinetix 5700 run on a non-Rockwell PLC?
Kinetix 5700 is built for Integrated Motion on EtherNet/IP with Logix controllers, and its manual describes configuration in Studio 5000 Logix Designer. On a non-Logix controller, a drive with a native EtherCAT or PROFINET interface is usually the simpler choice.
Do Yaskawa Sigma-7 absolute encoders need a battery?
Yes. Sigma-7 absolute encoders keep their multiturn data on a battery. Below about 2.7 V the drive raises A.830 (Encoder Battery Alarm) or warning A.930. Yaskawa’s procedure is to replace the battery with only control power on, then cycle control power to clear A.830.
What is the Mitsubishi equivalent of Yaskawa A.C90?
On MR-J5 it is AL. 016 (Encoder initial communication error 1) if the fault appears at power-up, or AL. 020 (Encoder normal communication error 1) if it appears while running. MR-J4 uses AL.16 and AL.20 for the same two cases.
What does Kinetix 5700 FLT S54 mean?
FLT S54 – POSN ERROR is an Excessive Position Error fault: the difference between commanded and actual position exceeded the configured limit. Check for binding or a dragging brake, then torque limits, acceleration and tuning. Rockwell’s 2198-RD003 reference and online lookup give the full corrective actions.
Which is easiest to tune?
All three offer tuning-free start-up: Yaskawa’s tuning-less function, Mitsubishi’s one-touch and quick tuning, and Rockwell’s default load observer with adaptive tuning. Ease in practice depends more on inertia ratio and machine stiffness than on the brand.