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: 1200, 2400, 4800, 9600, 19200, 38400 |
| Data · parity · stop | 8 · None · 2 |
| Slave ID (factory) | 1 (1~99) |
| Manual address style | Wire address as is (0-based) |
- Defaults from comm manual 3.2 MT4N (printed p.32 = PDF p.33): addr 01, 9600, NONE, stop 2, wait 5 ms. 8 data bits, speeds and max 31 units (address 01-99) from product manual TCD210231AI p.3.
- Manual writes «300001(0000)»: 1-based reference + hex comm address; first entries are (0000), so the parenthesized value is the 0-based wire address (printed pp.27-29). Frame examples show layout only.
- Broadcast is not supported (comm manual, PDF p.6).
Registers (31)
«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.
31
Swipe the table sideways — the first column (manual address) stays put.
| Manual | Wire | Table | Name | Type | Unit · scale | R/W | FC | Details |
|---|---|---|---|---|---|---|---|---|
| 300001(0000) | 0 (0x0000) | IR | Measured value | S16 | R | 04 | STND shows -5 to 110 %, SCAL -1999 to 9999. Sent as an integer; decimal point position in 300002(0001). 30000 = HHHH · -30000 = LLLL · 30001 = d-HH · -30001 = d-LL · 30002 = F-HH printed p.27 Table 2.3.1 (PDF p.28) | |
| 300002(0001) | 1 (0x0001) | IR | Decimal point / display mode | U16 | R | 04 | High byte = mode (0 STND, 1 SCAL, 2 FREQ), low byte = decimal places (0-3). E.g. SCAL 0.00 → 0102H. printed p.27 Table 2.3.1 (PDF p.28) | |
| 300003(0002) | 2 (0x0002) | IR | HI peak value | S16 | R | 04 | Sent as an integer; decimal point position in 300002(0001). printed p.27 Table 2.3.1 (PDF p.28) | |
| 300004(0003) | 3 (0x0003) | IR | LO peak value | S16 | R | 04 | Sent as an integer; decimal point position in 300002(0001). printed p.27 Table 2.3.1 (PDF p.28) | |
| 300005(0004) | 4 (0x0004) | IR | OUT status | U16 | R | 04 | 0 = OFF · 1 = ON printed p.27 Table 2.3.1 (PDF p.28) | |
| 300101(0064) | 100 (0x0064) | IR | Product number H | U16 | R | 04 | 0672H printed p.27 Table 2.3.1 (PDF p.28) | |
| 300102(0065) | 101 (0x0065) | IR | Product number L | U16 | R | 04 | 45660 = DV · 45760 = DA · 45860 = AV · 45960 = AA printed p.27 Table 2.3.1 (PDF p.28) | |
| 300104(0067) | 103 (0x0067) | IR | Software version | U16 | R | 04 | printed p.27 Table 2.3.1 (PDF p.28) | |
| 100001(0000) | 0 (0x0000) | DI | Out status OUT1 | BIT | R | 02 | 0 = OFF · 1 = ON printed p.28 Table 2.3.2 (PDF p.29) | |
| 400001(0000) | 0 (0x0000) | HR | OUT1 high preset | S16 | R/W | 03·06·10 | Sent as an integer; decimal point position in 300002(0001). printed p.28 Table 2.3.3.1 (PDF p.29) | |
| 400002(0001) | 1 (0x0001) | HR | OUT1 low preset | S16 | R/W | 03·06·10 | Sent as an integer; decimal point position in 300002(0001). printed p.28 Table 2.3.3.1 (PDF p.29) | |
| 400005(0004) | 4 (0x0004) | HR | High peak | S16 | R/W | 03·06·10 | Factory default 0. Sent as an integer; decimal point position in 300002(0001). printed p.28 Table 2.3.3.1 (PDF p.29) | |
| 400006(0005) | 5 (0x0005) | HR | Low peak | S16 | R/W | 03·06·10 | Factory default 0. Sent as an integer; decimal point position in 300002(0001). printed p.28 Table 2.3.3.1 (PDF p.29) | |
| 400101(0064) | 100 (0x0064) | HR | Input range | U16 | R/W | 03·06·10 | Only refers to the measurement input specification for codes. printed p.28 Table 2.3.3.2 (PDF p.29) | |
| 400102(0065) | 101 (0x0065) | HR | Display | U16 | R/W | 03·06·10 | 0 = STND · 1 = SCAL · 2 = FREQ printed p.28 Table 2.3.3.2 (PDF p.29) | |
| 400103(0066) | 102 (0x0066) | HR | Dot | U16 | R/W | 03·06·10 | 0-3; value names are 7-segment symbols only, so digit meaning is not asserted. Range 0 ~ 3 printed p.28 Table 2.3.3.2 (PDF p.29) | |
| 400104(0067) | 103 (0x0067) | HR | High scale | S16 | R/W | 03·06·10 | Range -1999 ~ 9999 printed p.28 Table 2.3.3.2 (PDF p.29) | |
| 400105(0068) | 104 (0x0068) | HR | Low scale | S16 | R/W | 03·06·10 | Range -1999 ~ 9999 printed p.28 Table 2.3.3.2 (PDF p.29) | |
| 400106(0069) | 105 (0x0069) | HR | Input type (AC models) | U16 | R/W | 03·06·10 | 0 = T.RMS · 1 = A.RMS · 2 = AVG printed p.28 Table 2.3.3.2 (PDF p.29) | |
| 400107(006A) | 106 (0x006A) | HR | Display unit lamp | U16 | R/W | 03·06·10 | 0 = UNIT · 1 = mV · 2 = V · 3 = mA · 4 = A · 5 = Hz · 6 = OFF printed p.28 Table 2.3.3.2 (PDF p.29) | |
| 400201(00C8) | 200 (0x00C8) | HR | OUT1 type | U16 | R/W | 03·06·10 | 0 = OFF · 1 = HI · 2 = LO · 3 = HL · 4 = HL-G printed p.28 Table 2.3.3.3 (PDF p.29) | |
| 400207(00CE) | 206 (0x00CE) | HR | Display time | U16 | R/W | 03·06·10 | Manual range 0.1-5.0 s; raw scaling not stated. printed p.28 Table 2.3.3.3 (PDF p.29) | |
| 400208(00CF) | 207 (0x00CF) | HR | Color | U16 | R/W | 03·06·10 | 0 = RED · 1 = GRN · 2 = YEL · 3 = R-G · 4 = G-R printed p.28 Table 2.3.3.3 (PDF p.29) | |
| 400209(00D0) | 208 (0x00D0) | HR | Zero key | U16 | R/W | 03·06·10 | 0 = NO · 1 = YES printed p.28 Table 2.3.3.3 (PDF p.29) | |
| 400210(00D1) | 209 (0x00D1) | HR | Event input | U16 | R/W | 03·06·10 | 0 = HOLD · 1 = ZERO printed p.29 Table 2.3.3.3 (PDF p.30) | |
| 400213(00D4) | 212 (0x00D4) | HR | Address | U16 | R/W | 03·06·10 | Range 1 ~ 99 printed p.29 Table 2.3.3.3 (PDF p.30) | |
| 400214(00D5) | 213 (0x00D5) | HR | Bit per second | U16 | R/W | 03·06·10 | 0 = 1200 bps · 1 = 2400 bps · 2 = 4800 bps · 3 = 9600 bps · 4 = 19200 bps · 5 = 38400 bps printed p.29 Table 2.3.3.3 (PDF p.30) | |
| 400215(00D6) | 214 (0x00D6) | HR | Parity bit | U16 | R/W | 03·06·10 | 0 = NONE · 1 = EVEN · 2 = ODD printed p.29 Table 2.3.3.3 (PDF p.30) | |
| 400216(00D7) | 215 (0x00D7) | HR | Stop bit | U16 | R/W | 03·06·10 | 0 = 1 bit · 1 = 2 bits printed p.29 Table 2.3.3.3 (PDF p.30) | |
| 400217(00D8) | 216 (0x00D8) | HR | Response waiting time | U16 | ms | R/W | 03·06·10 | Range 5 ~ 99 ms printed p.29 Table 2.3.3.3 (PDF p.30) |
| 400218(00D9) | 217 (0x00D9) | HR | Lock | U16 | R/W | 03·06·10 | 0 = OFF · 1 = LOC1 · 2 = LOC2 · 3 = LOC3 printed p.29 Table 2.3.3.3 (PDF p.30) |
Notes
- RS485 only on output code 4 (relay OUT1 + RS485) (product manual p.2). □ = power code (E: 12-24 VDC/VAC, 4: 100-240 VAC).
- OUT2 preset/type/hysteresis are listed but marked 'Unable to set' or don't apply to the RS485 model (OUT1 only), so they are omitted.
- MT4W/MT4Y tables in the same manual use different holding addresses; this file is MT4N only. Printed page = PDF page - 1.
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
- autonics/mt4n.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
- User Manual for Communication 4-Digit Multi Panel Meters MT Series MCT-MTC1-V1.7-EN — Autonics, MCT-MTC1-V1.7-EN (2024-11-26) · printed pp.27-29 (PDF pp.28-30) MT4N mapping table, printed p.32 (PDF p.33) factory defaults · checked 2026-10-22
- 4-Digit Multi Panel Meters MT4N Series PRODUCT MANUAL TCD210231AI — Autonics, MT4N_EN_TCD210231AI_20260402 · p.2 ordering information, p.3 Communication Interface · checked 2026-10-22