Mitsubishi M80/M70 Servo Parameters: #2201-#2210 Full Table, #2233/#2238/#2246 Resonance Filters, #2235/#2237 Load Inertia Setup

Mitsubishi M80 / M70 servo adjustment comes down to a handful of parameter numbers. This page puts the whole chain in one place: the #2201–#2210 block (gear ratio, position loop, speed loop, current loop), the #2233 / #2238 / #2246 resonance-suppression trio, and the #2235 → #2237 load inertia identification routine — plus the traps that cost people the most time: SHG and OMR-FF are mutually exclusive, and servo alarm 37 is a gear-ratio problem, not a gain problem.

Scope: parameter numbers, abbreviations, setting ranges and standard values are taken from Mitsubishi Electric official documentation (M800/M80/E80/C80 Series Alarm/Parameter Manual, M800V/M80V Series Parameter Manual, MDS-E/EH Series Instruction Manual, M800S/M80 Series Connection and Setup Manual). Only numbers, names and ranges are referenced — no manual text is reproduced. Ranges differ slightly between drive-unit generations; where that matters it is flagged as *verify on your machine*.

1. Parameter Map: Four Families and the # ↔ SV Conversion

Mitsubishi CNC parameters are all # numbers grouped by function, and the group boundaries match the screens you set them on. Two naming systems describe the same value: the NC side uses # numbers (Maintenance → Param → Servo param), while drive-unit documentation uses SVxxx. The conversion is simple: SV number = # number − 2200. So #2201 = SV001, #2238 = SV038, #2246 = SV046, #2257 = SV057.

Mitsubishi parameter families and where each one lives

Family	Number range	Typical members
Base specification	#1001 – #1xxx	#1001 SYS_ON, #1002 axisno, #1003 iunit, #1004 ctrl_unit
Axis specification (per axis)	#2001 – #2100s	#2001 rapid, #2007 G1 time constant, #2011/#2012 stroke limits, #2021 drive-unit I/F channel
Servo (this article)	#2201+	SV001 PC1 … SV0xx
Spindle (NC side)	#3001+	#3001 slimt1 …
Spindle drive	#13001+	SP001 …
Machine error compensation	#4000+	pitch error, backlash compensation
PLC constants / timers	#6401–#6496, #16000–#17455	bit selection, T/C devices
Machining (user level)	#8000–#8999	#8008 corner decel angle, #8211 mirror image

Two conventions to internalise before you touch anything:

• (PR) in the manual means the setting only takes effect after a power cycle. #2201 and #2202 are both (PR).
• Some parameters are bit-select types written in hexadecimal. #2233 SV033 is the classic example — writing a decimal number there does something completely different from what you intended.

2. #2201–#2210: The Complete Block

Ten parameters, and only three of them are tuning parameters you should actually be moving.

Servo parameters #2201–#2210 (SV001–SV010)

#	SV	Abbrev	Name	Standard / note	Range
#2201	SV001	PC1	Motor side gear ratio	Set to 1 when no gearing; (PR)	1 – 32767
#2202	SV002	PC2	Machine side gear ratio	Set to 1 when no gearing; (PR)	1 – 32767
#2203	SV003	PGN1	Position loop gain 1	Standard 33	1 – 200 (rad/s)
#2204	SV004	PGN2	Position loop gain 2	PGN1 × 8/3 with SHG; 0 without SHG; 0 with OMR-FF	0 – 999 (rad/s)
#2205	SV005	VGN1	Speed loop gain 1	Motor-dependent; target the standard value for motor type + inertia ratio	1 – 30000
#2206	SV006	VGN2	Speed loop gain 2	Used with #2229 for high-speed vibration	—
#2207	SV007	VIL	Speed loop delay compensation	Motor standard value	—
#2208	SV008	VIA	Speed loop advance compensation	Standard 1364; 1900 with SHG	—
#2209	SV009	IQA	Current loop q-axis advance compensation	Motor standard value	—
#2210	SV010	IDA	Current loop d-axis advance compensation	Motor standard value	—

🚨 The most common mislabelling online: many “Mitsubishi servo parameter guides” call #2201 the position loop gain and #2202 the speed loop gain. They are not — #2201/#2202 are the electronic gear ratio (PC1/PC2). The official Alarm/Parameter Manual lists #2203 as PGN1 (position loop gain 1) and #2205 as VGN1 (speed loop gain 1). Mistaking PC1 for PGN1 means you retune the wrong number *and* you will hit servo alarm 37 (section 7).

2.1 The gain trio and what raising / lowering each one does

PGN1 / PGN2 / VGN1 — adjustment direction and symptoms

Parameter	Raise it when…	Too high looks like…	Too low looks like…
#2203 PGN1	Positioning takes too long, contour error at corners	Bigger shock on the machine during accel/decel; overshoot; vibration on reversal	Sluggish positioning, large following error, rounded corners
#2204 PGN2	Enabling SHG (must be PGN1 × 8/3)	—	0 disables SHG
#2205 VGN1	Rough surface, poor circle shape, low rigidity	Vibration / resonance; audible growl during rapid traverse	Soft response, chatter marks

The manual’s own guidance for VGN1 is worth quoting in spirit: if vibration occurs, lower it by 20–30 %, and settle at 70–80 % of the value at which the vibration stops. Do not chase the highest possible number.

3. Tuning Order: Speed Loop First, Always

The servo loop is nested — current loop inside, speed loop in the middle, position loop outside. The inner loop must respond faster than the outer one. Breaking that order is the single most common reason a machine “never settles down”.

1. Speed loop first. Raise #2205 VGN1 until the axis just starts to vibrate, then drop back to 70–80 % of that value. If vibration appears at any point, lower by 20–30 % and re-test.
2. Then position loop. Raise #2203 PGN1 from the standard 33 until the shock on accel/decel becomes unacceptable, then back off. On interpolating axes, set PGN1 to the same value on every axis — mismatched position loop gains distort circles and contours.
3. Only then add the advanced functions — #2208 VIA, #2215 FFC, SHG or OMR-FF. All of them assume the base loops are already stable.
4. If resonance forces VGN1 down, reduce PGN1 to match. A high position loop gain on top of a low speed loop gain guarantees vibration and overshoot during accel/decel.

Rule of thumb from the field: 80 % of “servo tuning” complaints are actually mechanical — backlash, coupling preload, worn guides, insufficient clamping. Filter out mechanical problems before you start trading gain numbers, or you will spend a day tuning around a loose coupling.

4. Resonance Suppression: #2233 / #2238 / #2246

Mitsubishi drive units carry multiple notch filters. The workflow for the first two is officially documented and takes about five minutes:

1. Raise #2205 VGN1 until resonance appears; back it off slightly and keep that value.
2. Diagn → Drv mon → Servo unit — read the “AFLT frequency” display. This is the drive unit’s own measurement of the resonance frequency. (*AFLT = 0 means no resonance is detected.*)
3. Mainte → Param → Servo param — write the AFLT value into #2238 SV038 FHz1 (notch filter frequency 1).
4. Move the axis again. If it still vibrates, read AFLT again and write the second frequency into #2246 SV046 FHz2 (notch filter frequency 2).
5. Tune the depth with #2233 SV033 SSF2 — start deep and make it shallower until the resonance just disappears.

#2233 SV033 — notch filter depth bits and resulting attenuation

Code (3 bits)	Attenuation	Applies to
000	−∞ (deepest)	bit3-1 nfd1 → depth of filter 1 (#2238)
001	−18.1 dB	bit7-5 nfd2 → depth of filter 2 (#2246)
010	−12.0 dB	(same bit pattern for both filters)
011	−8.5 dB
100	−6.0 dB
101	−4.1 dB
110	−2.5 dB
111	−1.2 dB (shallowest)

Four details that save repeat visits:

• 🚨 Set the depth as shallow as works. The manual is explicit: setting a notch filter to a very low frequency can make a *latent* resonance appear, and an unnecessarily deep filter degrades servo stability. Deeper is not better.
• Notch filter 3 is fixed at 1125 Hz and has no depth compensation — it is switched on/off by #2233 bit 4 (fhz3), not tuned.
• Setting range is generation-dependent. M800/M80/E80/C80 documentation lists 0–5000 Hz for #2238/#2246; some drive-unit manuals list 0–2250 Hz or 0–4500 Hz, and state the filter is only valid at 36 Hz or above. Check your drive unit’s manual.
• AFLT readings must be rounded to the drive unit’s settable resolution. A widely circulated field example converts a measured 235 Hz to a setting of 225 Hz and 396 Hz to 391 Hz — treat that as an illustration only, *verify against your drive unit*.

Newer drive units add notch filters 4 and 5; the M80V PLC manual lists #2287 and #2288 alongside #2233/#2238/#2246 as resonance-filter related parameters. Their exact names should be confirmed in your drive-unit manual.

5. Load Inertia Identification: #2235 → #2237

#2237 SV037 JL is the load inertia scale, and it is not optional — the disturbance observer, real-time tuning and OMR-FF all read it. The definition is:

SV037 (JL) = (Jm + Jl) / Jm × 100 where Jm = motor inertia and Jl = load inertia converted to the motor shaft. For a linear motor, set the gross moving mass in kg. Range: 0–5000 (%) (0–5000 kg for linear).

The measurement routine

1. Zero first. Confirm #2232 (SV032, imbalance torque), #2245 (SV045, friction torque) and #2237 are all 0.
2. Enable the display flag. Set #2235 SV035 bit F = 1 — i.e. write 8* (commonly written as 8000**) into #2235.
3. Measure friction torque #2245. Park the table at mid-stroke, then run each axis back and forth 200 mm at F1000 with a 0.5 s dwell at each reversal. On Diagn → Drv mon, read the servo load current in both directions: friction torque = |(+ direction %) − (− direction %)| / 2. Example: +20 % and −20 % → |20 − (−20)| / 2 = 20 → set #2245 = 20.
4. Measure imbalance torque #2232 — only for unbalanced (typically vertical) axes, using the same program: imbalance torque = ((+ %) + (− %)) / 2. Example: +30 % and −20 % → (30 + (−20)) / 2 = 5 → set #2232 = 5. The sign of #2232 also decides the pull-up direction for the vertical axis function.
5. Read the inertia ratio. Change the G01 to G00 in the same program, ramp the rapid override up to 100 %, and read the load inertia ratio on the drive monitor. Take the average of several passes.
6. Write it into #2237, then set #2235 back to 0000.
7. Recommended follow-up: #2243 SV043 OBS1 = 100 and #2244 SV044 OBS2 = 100 for the disturbance observer. Changing observer parameters requires re-adjusting lost-motion compensation.

A field rule of thumb: if the measured load inertia ratio exceeds roughly 350, the selected motor’s torque is too small for the machine and a larger motor should be considered. Treat this as a selection guideline, not a hard limit — *verify on your machine*.

If you use real-time tuning, also set #2399 RTGM (non-zero) and #2400 RTJX (larger than #2237); the speed gain switches with the estimated inertia between those two bounds.

6. SHG vs OMR-FF vs NC Analyzer2

These three are constantly confused. They are different layers.

SHG / OMR-FF / NC Analyzer2 — what each one actually is

	SHG control	OMR-FF control	NC Analyzer2
What it is	A control mode inside the drive	A control mode inside the drive	A PC software tool (Ethernet)
Purpose	Higher position loop gain with smooth accel/decel	Better arc inner-rounding, corner error and path vibration	Measure machine characteristics and set parameters
Key parameters	#2203 PGN1, #2204 PGN2, #2257 SHGC	#2306 SV106 PGM, #2312 SV112 IFF, #2313 SV113 bit0	— (writes the parameters for you)
Requirement	PGN1 : PGN2 : SHGC = 1 : 8/3 : 6	NC-side OMR-FF option; #2237 must be set first	Windows 10/11; M800/M80/E80/C70… series

SHG (Smooth High-Gain). Compensates the position-loop delay more stably, so the same PGN1 setting yields roughly double the effective position loop gain. Parameter ratio is mandatory: PGN1 : PGN2 : SHGC = 1 : 8/3 : 6. Companion values: #2208 VIA 1364 → 1900, #2215 FFC 0 → 100.

OMR-FF. Builds separate feed-forward commands for position, speed and current from a scale model, letting you set command tracking (PGM) and servo rigidity (PGN) independently. Enable it with #2313 SV113 bit0 (omrffon) = 1; then #2306 SV106 PGM = same value as #2203 PGN1, and #2312 SV112 IFF standard 10000 (0.01 % units).

🚨🚨 SHG and OMR-FF are mutually exclusive. The MDS-E manual states plainly: disable SHG control when using OMR-FF — and #2204 PGN2 must be set to 0 in OMR-FF mode. Two more cautions from the same manual: always set the load inertia scale (#2237) before adjusting OMR-FF, and while OMR-FF is enabled the estimated inertia value displays as 0 (so you cannot measure inertia with OMR-FF on).

NC Analyzer2 is the official PC tool that automates the measuring: adjustment wizard, speed loop gain adjustment, notch filter setting, circularity adjustment, Bode diagram measurement and servo waveform capture, over Ethernet, on Windows 10/11, with a Simplified Chinese interface. It supports M800V/M80V/M800/M80/E80/C80 and the M700/M70/C70 generation. Use it when you do not have a vibration analyser — it replaces the guesswork in sections 4 and 5 with an actual frequency response plot.

7. Servo Alarm 37 and #2201 / #2202

Servo alarm 37 is an initial parameter error caused by electronic gear overflow — and the official manual warns about it in the description of both #2201 and #2202:

“Even if the gear ratio is within the setting range, the electronic gears may overflow and an initial parameter error (servo alarm 37) may occur.”

What that means in practice:

• It is not a gain problem and not a drive fault. Raising or lowering PGN1/VGN1 will not clear it.
• It fires at power-on, when the NC computes the electronic gear ratio from #2201/#2202 together with the detector resolution.
• Reduce #2201/#2202 to the simplest integer ratio before anything else. A gear ratio entered as a large non-reduced pair overflows even though each individual number is inside 1–32767.
• If it still trips, check the mechanical reduction ratio and detector resolution against your drive unit’s manual. The exact overflow threshold is generation-specific — *verify on your machine*.
• Remember both parameters are (PR): power OFF/ON after changing them.

8. Backup and Rollback Discipline

Servo parameters are the easiest thing on the machine to destroy and the hardest to reconstruct from memory.

1. Back up before every tuning session, not after. The current state is the only known-good fallback you have.
2. Change one parameter at a time, and record the old value, the new value and the symptom you were chasing.
3. Power-cycle discipline: (PR) parameters (#2201, #2202, …) do nothing until you cycle power. If “nothing changed”, check that first.
4. Re-mechanical-check before re-tuning. If a machine that used to be quiet starts vibrating, suspect the mechanics before you start moving gains — you will otherwise tune the machine into a state nobody can reproduce.
5. Keep the motor-standard block (#2206–#2213) sacred. These come from the motor parameter list for your specific motor type; they are not tuning knobs.

9. FANUC ↔ Mitsubishi Cross-Reference

If you came from FANUC, this is the translation table you want — and the caveat that matters more than the table.

FANUC ↔ Mitsubishi servo parameter analogy

Function	FANUC	Mitsubishi M80	Note
Position loop gain	1825 (0.01 s⁻¹, tuning start 5000)	#2203 PGN1 (rad/s, standard 33)	Same role, different unit and scale
Load inertia ratio / velocity gain	2021 (tuning start 128)	#2237 JL (%) + #2205 VGN1	Different definitions — see below
Backlash acceleration	2048 (100)	#2227 bit4/bit5 jitter comp., #2240 LMCT	Not a 1:1 equivalent
Feed-forward	2005/2092 (AI contour / FF)	#2215 FFC, #2208 VIA	Different decomposition
Servo tuning software	SERVO GUIDE / Servo Viewer	NC Analyzer2	Both measure + plot

🚨 Do not copy numbers across. The definitions genuinely differ:

• FANUC 2021 is a load inertia ratio whose relation to velocity loop gain is: velocity loop gain (%) = (1 + load inertia ratio / 256) × 100 — so 2021 = 128 gives 150 %.
• Mitsubishi #2237 is (Jm + Jl) / Jm × 100, i.e. a percentage of *total* inertia including the motor. A value of 100 means “no external load”.

They are conceptually related but numerically incompatible. Use the table to find *which parameter to open*, then set it by measurement on your own machine.

For the FANUC side worked out in detail, see FANUC servo gain tuning: 2021, 1825, 2020 and the correct order; for diagnosing what the vibration itself is telling you before you touch any gain, see servo vibration, overshoot and abnormal noise: symptom-based diagnosis.

Which Mitsubishi parameter is the position loop gain and which is the speed loop gain?

#2203 (SV003, PGN1) is the position loop gain 1 and #2205 (SV005, VGN1) is the speed loop gain 1. #2204 (SV004, PGN2) is position loop gain 2, used only with SHG control and set to PGN1 × 8/3 (or 0 when SHG is not used). Beware the widespread online error that labels #2201/#2202 as gains — those two are the electronic gear ratio (PC1 motor side, PC2 machine side) and have nothing to do with gain.

How do I stop resonance on a Mitsubishi machine, and what goes into #2238?

Raise #2205 VGN1 until resonance appears and back it off slightly. Then read the AFLT frequency on Diagn → Drv mon → Servo unit, and write that frequency into #2238 (SV038, notch filter frequency 1). Move the axis again; if it still vibrates, read AFLT a second time and put that frequency into #2246 (SV046, notch filter frequency 2). Finally tune the filter depth with #2233 (SV033): bits 3-1 set the depth of filter 1 and bits 7-5 the depth of filter 2, from 000 (−∞, deepest) through 100 (−6.0 dB) to 111 (−1.2 dB, shallowest). Set #2233 in hexadecimal. Aim for the shallowest depth that removes the resonance — an unnecessarily deep filter hurts stability, and a filter set too low can expose a latent resonance at another frequency.

How do I measure the load inertia ratio on a Mitsubishi M80?

Set #2232, #2245 and #2237 to 0, then set #2235 bit F = 1 (SV035 written as 8*, commonly 8000). Run each axis back and forth 200 mm at F1000 from mid-stroke and read the servo load current on the drive monitor: friction torque #2245 = |(+ %) − (− %)| / 2, and for unbalanced axes imbalance torque #2232 = ((+ %) + (− %)) / 2. Then switch the move to G00, ramp the rapid override to 100 %, take the average of the displayed load inertia ratio, write it into #2237 (SV037 JL), and set #2235 back to 0000**. Afterwards set #2243 = 100 and #2244 = 100 and re-adjust lost-motion compensation.

*Last updated: 2026-10-23*