An unofficial summary of facts (addresses, types, units, scaling) from the maker's manual. Not affiliated with the maker; values can differ by firmware or model. Always check the device manual before writing (run commands, settings).
Default communication
| Protocol | Modbus RTU |
|---|---|
| Baud (factory) | 9600 bps — options: 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 76800, 115200 |
| Data · parity · stop | 8 · Even · 1 |
| Max per request | 125 registers |
| Manual address style | 40001/30001 style (wire address + 1, first digit = table) |
- Addressing: the read example (p.719 (PDF 720)) sends 11 03 03 EB 00 03 77 2B to read 41004-41006 (Pr.4-6); the write example (p.720 (PDF 721)) 05 06 00 0D 17 70 17 99 writes 60 Hz to 40014; the FC10 example (p.721 (PDF 722)) 19 10 03 EE 00 02 04 00 05 00 0A 86 3D writes 41007 and 41008. Frame address = manual number - 40001. CRCs match calculation.
- To use Modbus RTU set Pr.549 = 1 (default 0 = Mitsubishi protocol). These are the RS-485 terminal settings, not the PU connector: Pr.331 station default 0 is broadcast (no reply), so set 1-247; Pr.332 default 96 = 9600 bps; Pr.334 default 2 = even parity, 1 stop bit (Pr.333 stop bits apply only when Pr.334 = 0); 8 data bits fixed (p.715-716 (PDF 716-717)).
- Function codes 03, 06, 08, 10, 46. Up to 125 registers per read/write. With a communication option installed and Pr.550 = 9999 (initial), operation commands via the RS-485 terminals are invalid.
Registers (33)
«Wire» is the 0-based address in the request frame (PortDock's «0-based» notation). Value = raw × scale. Table: HR holding register, IR input register, CO coil, DI discrete input. Function codes in hex.
33
Swipe the table sideways — the first column (manual address) stays put.
| Manual | Wire | Table | Name | Type | Unit · scale | R/W | FC | Details |
|---|---|---|---|---|---|---|---|---|
| 40002 | 1 (0x0001) | HR | Inverter reset | U16 | W | 06·10 | Write any value. No reply to the reset command p.723 (PDF 724) | |
| 40009 | 8 (0x0008) | HR | Inverter status / control input command | U16 | R/W | 03·06·10 | Write = control input, read = inverter status. Signals in brackets are initial assignments; inputs change with Pr.180-189, outputs with Pr.190-196 b0 Write: stop / Read: RUN (running) · b1 Write: forward rotation / Read: forward running · b2 Write: reverse rotation / Read: reverse running · b3 Write: RH (high speed) / Read: SU (up to frequency) · b4 Write: RM (middle speed) / Read: OL (overload warning) · b5 Write: RL (low speed) / Read: IPF (instantaneous power failure/undervoltage) · b6 Write: JOG (jog operation) / Read: FU (frequency detection) · b7 Write: RT (second function selection) / Read: ABC1 (fault) · b8 Write: AU (terminal 4 input selection) / Read: ABC2 · b9 Write: CS (automatic restart after instantaneous power failure) / Read: Safety monitor output · b10 Write: MRS (output stop) · b11 Write: STP (STOP, start self-holding) · b12 Write: RES (inverter reset) · b15 Read: fault occurrence p.724 (PDF 725) | |
| 40010 | 9 (0x0009) | HR | Operation mode / inverter setting | U16 | R/W | 03·06·10 | Values are the read mode. Write: 0010h = EXT, 0011h = PU (depending on Pr.79/Pr.340), 0014h = NET 0 = EXT · 1 = PU · 2 = EXT JOG · 3 = PU JOG · 4 = NET · 5 = PU+EXT p.724 (PDF 725) | |
| 40014 | 13 (0x000D) | HR | Set frequency (RAM) | U16 | ×0.01 Hz | R/W | 03·06·10 | 0.01 Hz with initial settings (Pr.37 = 0, Pr.144 = 2-12); changes to rotation/machine speed (increment 1) depending on Pr.37/Pr.144. Manual FC06 example: 60 Hz = 1770h p.723 (PDF 724) |
| 40015 | 14 (0x000E) | HR | Set frequency (EEPROM) | U16 | ×0.01 Hz | W | 06·10 | p.723 (PDF 724) |
| 40201 | 200 (0x00C8) | HR | Output frequency | U16 | ×0.01 Hz | R | 03 | 0.01 Hz with initial settings (Pr.37 = 0, Pr.144 = 2-12); changes to rotation/machine speed (increment 1) depending on Pr.37/Pr.144 p.464-465 (PDF 465-466) |
| 40202 | 201 (0x00C9) | HR | Output current | U16 | ×0.01 A | R | 03 | 0.01 increments for FR-A820-03160 (55K) / FR-A840-01800 (55K) or lower; 0.1 for larger capacities p.464-465 (PDF 465-466) |
| 40203 | 202 (0x00CA) | HR | Output voltage | U16 | ×0.1 V | R | 03 | p.464-465 (PDF 465-466) |
| 40205 | 204 (0x00CC) | HR | Set frequency | U16 | ×0.01 Hz | R | 03 | 0.01 Hz with initial settings (Pr.37 = 0, Pr.144 = 2-12); changes to rotation/machine speed (increment 1) depending on Pr.37/Pr.144 p.464-465 (PDF 465-466) |
| 40206 | 205 (0x00CD) | HR | Operation speed | U16 | r/min | R | 03 | p.464-465 (PDF 465-466) |
| 40207 | 206 (0x00CE) | HR | Motor torque | U16 | ×0.1 % | R | 03 | p.464-465 (PDF 465-466) |
| 40208 | 207 (0x00CF) | HR | Converter output voltage | U16 | ×0.1 V | R | 03 | p.464-465 (PDF 465-466) |
| 40209 | 208 (0x00D0) | HR | Regenerative brake duty | U16 | ×0.1 % | R | 03 | p.464-465 (PDF 465-466) |
| 40210 | 209 (0x00D1) | HR | Electronic thermal O/L relay load factor | U16 | ×0.1 % | R | 03 | p.464-465 (PDF 465-466) |
| 40211 | 210 (0x00D2) | HR | Output current peak value | U16 | ×0.01 A | R | 03 | 0.01 increments for FR-A820-03160 (55K) / FR-A840-01800 (55K) or lower; 0.1 for larger capacities p.464-465 (PDF 465-466) |
| 40212 | 211 (0x00D3) | HR | Converter output voltage peak value | U16 | ×0.1 V | R | 03 | p.464-465 (PDF 465-466) |
| 40213 | 212 (0x00D4) | HR | Input power | U16 | ×0.01 kW | R | 03 | 0.01 increments for FR-A820-03160 (55K) / FR-A840-01800 (55K) or lower; 0.1 for larger capacities p.464-465 (PDF 465-466) |
| 40214 | 213 (0x00D5) | HR | Output power | U16 | ×0.01 kW | R | 03 | 0.01 increments for FR-A820-03160 (55K) / FR-A840-01800 (55K) or lower; 0.1 for larger capacities p.464-465 (PDF 465-466) |
| 40215 | 214 (0x00D6) | HR | Input terminal status | U16 | R | 03 | b0 STF · b1 STR · b2 AU · b3 RT · b4 RL · b5 RM · b6 RH · b7 JOG · b8 MRS · b9 STP (STOP) · b10 RES · b11 CS · b14 S2 · b15 S1 p.467-468 (PDF 468-469) | |
| 40216 | 215 (0x00D7) | HR | Output terminal status | U16 | R | 03 | b0 RUN · b1 SU · b2 IPF · b3 OL · b4 FU · b5 ABC1 · b6 ABC2 · b7 SO p.467-468 (PDF 468-469) | |
| 40220 | 219 (0x00DB) | HR | Cumulative energization time | U16 | h | R | 03 | Accumulates 0-65535 h, then restarts from 0 (overflow count in Pr.563) p.464-465 (PDF 465-466) |
| 40223 | 222 (0x00DE) | HR | Actual operation time | U16 | h | R | 03 | Accumulates 0-65535 h, then restarts from 0 (overflow count in Pr.564) p.464-465 (PDF 465-466) |
| 40224 | 223 (0x00DF) | HR | Motor load factor | U16 | ×0.1 % | R | 03 | p.464-465 (PDF 465-466) |
| 40261 | 260 (0x0104) | HR | Motor thermal load factor | U16 | ×0.1 % | R | 03 | p.467 (PDF 468) |
| 40262 | 261 (0x0105) | HR | Inverter thermal load factor | U16 | ×0.1 % | R | 03 | p.467 (PDF 468) |
| 40277 | 276 (0x0114) | HR | 32-bit cumulative energy (kWh) | U32 CDAB | kWh | R | 03 | 40277 = lower 16 bits, 40278 = upper 16 bits (word swap, CDAB) p.468 (PDF 469) |
| 40279 | 278 (0x0116) | HR | 32-bit cumulative energy (0.01 kWh) | U32 CDAB | ×0.01 kWh | R | 03 | 40279 = lower 16 bits, 40280 = upper 16 bits (word swap, CDAB). 0.01 kWh for FR-A820-03160(55K) / FR-A840-01800(55K) or lower; 0.1 kWh for larger capacities p.468 (PDF 469) |
| 40501 | 500 (0x01F4) | HR | Fault record 1 (latest) | U16 | R/W | 03·06·10 | Low byte is the fault code (00xxh). Writing any value clears the whole fault history p.726 (PDF 727) | |
| 40502 | 501 (0x01F5) | HR | Fault record 2 | U16 | R | 03 | Same format up to 40508 (fault record 8) p.726 (PDF 727) | |
| 41007 | 1006 (0x03EE) | HR | Acceleration time (Pr.7) | U16 | ×0.1 s | R/W | 03·06·10 | Register = parameter number + 41000. 0.1 s units with Pr.21 = 0 (initial); 0.01 s with Pr.21 = 1. Manual FC10 example: 0.5 s = 0005h p.721 (PDF 722) |
| 41008 | 1007 (0x03EF) | HR | Deceleration time (Pr.8) | U16 | ×0.1 s | R/W | 03·06·10 | 0.1 s units with Pr.21 = 0 (initial); 0.01 s with Pr.21 = 1. Manual FC10 example: 1 s = 000Ah p.721 (PDF 722) |
| 44001 | 4000 (0x0FA0) | HR | Model name | STRING(20) | R | 03 | ASCII, 20 characters (44001-44010), blanks are 20h. Example FR-A840-1 → 46h 52h 2Dh ... p.726 (PDF 727) | |
| 44011 | 4010 (0x0FAA) | HR | Capacity | STRING(6) | R | 03 | ASCII, 6 characters (44011-44013), in 0.1 kW (0.01 kW truncated), blanks are 20h. Example 0.75K → " 7" p.726 (PDF 727) |
Notes
- Monitor registers (40201-) are taken from the 'MODBUS RTU' column of the monitor item list. Negative indication (○) in that table is not available over Modbus RTU, so all are listed as unsigned 16-bit.
- Current and power scales are for FR-A820-03160 (55K) / FR-A840-01800 (55K) or lower (scale 0.01); larger capacities use 0.1 increments.
- Cumulative energy 40225 is left out: the Modbus column of the monitor list says 0.01 kWh, but the cumulative power section of the same manual (p.471 (PDF 472)) gives 1 kWh increments via communication (0-9999 or 0-65535 kWh by Pr.170). The 32-bit cumulative energy registers (40277-40280), whose units are explicit, are included instead.
Read it with PortDock
- Install the free PortDock Modbus Master and connect with the device's settings.
- On the table toolbar, «Device profile…» → pick this device → «Load». Polling tables, names, types and the Slave ID are filled in (optionally the serial settings too).
- Names carry the unit and scale (e.g. «×0.01 Hz»). Values on screen are raw — multiply by the scale.
- To test your program without the device, PortDock Modbus Slave's «Emulate device…» serves the same map with example values.
Download JSON
- mitsubishi-electric/fr-a800.json (GitHub raw) · copy on this site · history
- schema.json — format (JSON Schema). table, address (0-based), type and order match the PortDock CSV.
- License: CC BY 4.0 — please cite:
PortDock device register maps, v2026.10 · 09ac1d0b2792, https://portdock.dev/devices/
and this page. LICENSE · data bundle, version and changelog - Found a mistake? Please open a GitHub issue with the manual page.
Sources
- FR-A800 INSTRUCTION MANUAL (DETAILED) — Mitsubishi Electric Corporation, IB(NA)-0600503ENG-P · Modbus RTU p.715 (PDF 716) to p.726 (PDF 727), monitor item list pp.462-469 (PDF 463-470), Pr.7/Pr.21 p.374 (PDF 375), cumulative power p.471 (PDF 472) · checked 2026-10-23