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Finder 7M.38 three-phase energy meter (Modbus RS485) Modbus register map
Updated 24 October 2026
The 7M.38 is Finder's three-phase MID energy meter for DIN rail. The RS485 version speaks Modbus RTU and offers the same measurements twice: as packed integer formats and as IEEE 754 floats. This map uses the float block (voltages, currents, powers, power factor, THD, frequency, energy counters) plus identification, status, tariff, reset and serial-port registers.
This page lists 72 Modbus registers for the Finder 7M.38 three-phase energy meter (Modbus RS485) — 13 writable — with the table, 0-based wire address, data type, word order, scale, units and access of each, re-typed from Finder’s own free documentation (linked below) and checked against it.
- Manufacturer
- Finder
- Model
- 7M.38 three-phase energy meter (Modbus RS485)
- Equipment type
- Energy meter
- Registers
- 72 (13 writable)
- Transport
- Modbus RTU
- Default unit ID
- Not stated
- Documented addressing
- Modicon 3xxxx/4xxxx (drop the prefix, subtract 1)
- 32-bit word order
- ABCD high word first (big-endian)
- Also known as
- 7M.38, 7M38, 7M.38.8.400.0212, 7M3884000212, Finder 7M38 Modbus
Integration notes: Finder 7M.38 three-phase energy meter (Modbus RS485)
Read input registers with function 04 and decode the IEEE 754 float block, high word first: subtract 30000 from the printed number (Pt at 32490 is wire 2490). Energy comes as floats in Wh/varh at 32752 onward.
Minimum registers to map
Addresses are 0-based wire addresses. Enough to monitor and run the unit; map more as the job needs.
| Register | Name | Type | Why | Access |
|---|---|---|---|---|
| IR 2500 | U1 | FLOAT32 ABCD | U1 voltage (float, V) | Read |
| IR 2516 | I1 | FLOAT32 ABCD | I1 current (float, A) | Read |
| IR 2490 | Active power total (Pt) | FLOAT32 ABCD | Total active power (float, W) | Read |
| IR 2496 | Power factor total (PFt) | FLOAT32 ABCD | Total power factor | Read |
| IR 2498 | Frequency | FLOAT32 ABCD | Frequency | Read |
| IR 2752 | Energy counter n1 | FLOAT32 ABCD | Energy counter n1 (float, Wh) | Read |
| IR 2756 | Energy counter n3 | FLOAT32 ABCD | Energy counter n3 (float, Wh) | Read |
Enable Modbus control & writes
Modbus RTU runs on the RS485 serial versions (7M.38.8.400.XXXX). Port 1 address, baud, stop bits and parity sit in registers 40202-40205; writing settings needs the access level raised first by writing the user password to 40001 (function 16), then save with operator command 40012 = 1.
Byte order & addressing
- The memory reference is 30000/40000, not 30001/40001: printed 30107 is wire address 107.
- Floats and 32-bit integers are high word first (ABCD).
- The integer measurement registers use a packed exponent format; use the float block for SCADA.
Network setup
- Modbus address 1-247; baud code range 1-7 (2400 to 115200 - code 0, 1200 baud, is listed but outside the allowed min/max); parity none/odd/even; 1 or 2 stop bits; 8 data bits only.
- The operator command register 40012 saves (1) or aborts (2) pending setting changes and can restart the instrument (3).
Watch out for
- Which energy counter is import and which is export depends on the counter configuration registers; verify against the display before billing.
- Read 30099 for the maximum number of registers the meter accepts per request.
Finder 7M.38 three-phase energy meter (Modbus RS485) Modbus registers
Address = 0-based wire address (the documented number is shown under it when it differs) · Order: ABCD = high word first, CDAB = low word first · Scale: engineering value = raw × scale.
| Table | Address | Name | Description | Type | Order | Scale | Units | Access | Values / bits |
|---|---|---|---|---|---|---|---|---|---|
| IR | 1doc 30001 | Model number | 16-character text, two characters per register. | STRING[16] | Read | ||||
| IR | 9doc 30009 | Serial number | 8-character text. | STRING[8] | Read | ||||
| IR | 13doc 30013 | Software version | UINT16 | Read | |||||
| IR | 44doc 30044 | Status register | BITMAP16 | Read | bit 0 = Locked; bit 4 = Clock not set | ||||
| IR | 76doc 30076 | MID lock status | UINT16 | Read | 0 = Unlocked; 1 = Locked | ||||
| IR | 99doc 30099 | Modbus max registers per read | Largest register count the meter accepts in one read. | UINT16 | Read | ||||
| IR | 101doc 30101 | Phase valid measurement | A set bit means that phase's measurement is invalid. | BITMAP16 | Read | bit 0 = Invalid measurement phase 1; bit 1 = Invalid measurement phase 2; bit 2 = Invalid measurement phase 3 | |||
| IR | 103doc 30103 | Run time | INT32 | ABCD | s | Read | |||
| IR | 197doc 30197 | External relay status | UINT16 | Read | 0 = Off; 1 = On; 250 = Comm. error; 255 = Not connected | ||||
| IR | 400doc 30400 | Checksum status | 0 = no error. | BITMAP16 | Read | bit 0 = Parameter CRC error; bit 1 = Firmware CRC error; bit 2 = MID-lock error; bit 3 = Phase module 1 checksum error; bit 4 = Phase module 2 checksum error; bit 5 = Phase module 3 checksum error; bit 6 = Measurement module checksum error; bit 7 = Software checksum error; bit 8 = Calibration data checksum error; bit 9 = MID setting data checksum error; bit 10 = Setting data checksum error; bit 11 = Phase module 1 calibration checksum error; bit 12 = Phase module 2 calibration checksum error; bit 13 = Phase module 3 calibration checksum error | |||
| IR | 405doc 30405 | Current active tariff | UINT16 | Read | |||||
| IR | 2480doc 32480 | Run time (float) | FLOAT32 | ABCD | s | Read | |||
| IR | 2484doc 32484 | Uavg phase-to-neutral | FLOAT32 | ABCD | V | Read | |||
| IR | 2486doc 32486 | Uavg phase-to-phase | FLOAT32 | ABCD | V | Read | |||
| IR | 2488doc 32488 | Sum of currents | Sum of the three phase currents. | FLOAT32 | ABCD | A | Read | ||
| IR | 2490doc 32490 | Active power total (Pt) | Signed float. | FLOAT32 | ABCD | W | Read | ||
| IR | 2492doc 32492 | Reactive power total (Qt) | FLOAT32 | ABCD | var | Read | |||
| IR | 2494doc 32494 | Apparent power total (St) | FLOAT32 | ABCD | VA | Read | |||
| IR | 2496doc 32496 | Power factor total (PFt) | FLOAT32 | ABCD | Read | ||||
| IR | 2498doc 32498 | Frequency | FLOAT32 | ABCD | Hz | Read | |||
| IR | 2500doc 32500 | U1 | Phase 1 to neutral. | FLOAT32 | ABCD | V | Read | ||
| IR | 2502doc 32502 | U2 | Phase 2 to neutral. | FLOAT32 | ABCD | V | Read | ||
| IR | 2504doc 32504 | U3 | Phase 3 to neutral. | FLOAT32 | ABCD | V | Read | ||
| IR | 2508doc 32508 | U12 | FLOAT32 | ABCD | V | Read | |||
| IR | 2510doc 32510 | U23 | FLOAT32 | ABCD | V | Read | |||
| IR | 2512doc 32512 | U31 | FLOAT32 | ABCD | V | Read | |||
| IR | 2516doc 32516 | I1 | FLOAT32 | ABCD | A | Read | |||
| IR | 2518doc 32518 | I2 | FLOAT32 | ABCD | A | Read | |||
| IR | 2520doc 32520 | I3 | FLOAT32 | ABCD | A | Read | |||
| IR | 2528doc 32528 | Iavg | Average phase current. | FLOAT32 | ABCD | A | Read | ||
| IR | 2530doc 32530 | Active power L1 (P1) | FLOAT32 | ABCD | W | Read | |||
| IR | 2532doc 32532 | Active power L2 (P2) | FLOAT32 | ABCD | W | Read | |||
| IR | 2534doc 32534 | Active power L3 (P3) | FLOAT32 | ABCD | W | Read | |||
| IR | 2538doc 32538 | Reactive power L1 (Q1) | FLOAT32 | ABCD | var | Read | |||
| IR | 2540doc 32540 | Reactive power L2 (Q2) | FLOAT32 | ABCD | var | Read | |||
| IR | 2542doc 32542 | Reactive power L3 (Q3) | FLOAT32 | ABCD | var | Read | |||
| IR | 2546doc 32546 | Apparent power L1 (S1) | FLOAT32 | ABCD | VA | Read | |||
| IR | 2548doc 32548 | Apparent power L2 (S2) | FLOAT32 | ABCD | VA | Read | |||
| IR | 2550doc 32550 | Apparent power L3 (S3) | FLOAT32 | ABCD | VA | Read | |||
| IR | 2554doc 32554 | Power factor L1 (PF1) | FLOAT32 | ABCD | Read | ||||
| IR | 2556doc 32556 | Power factor L2 (PF2) | FLOAT32 | ABCD | Read | ||||
| IR | 2558doc 32558 | Power factor L3 (PF3) | FLOAT32 | ABCD | Read | ||||
| IR | 2570doc 32570 | Angle U1-I1 | FLOAT32 | ABCD | ° | Read | |||
| IR | 2572doc 32572 | Angle U2-I2 | FLOAT32 | ABCD | ° | Read | |||
| IR | 2574doc 32574 | Angle U3-I3 | FLOAT32 | ABCD | ° | Read | |||
| IR | 2588doc 32588 | I1 THD | FLOAT32 | ABCD | % | Read | |||
| IR | 2590doc 32590 | I2 THD | FLOAT32 | ABCD | % | Read | |||
| IR | 2592doc 32592 | I3 THD | FLOAT32 | ABCD | % | Read | |||
| IR | 2594doc 32594 | U1 THD | FLOAT32 | ABCD | % | Read | |||
| IR | 2596doc 32596 | U2 THD | FLOAT32 | ABCD | % | Read | |||
| IR | 2598doc 32598 | U3 THD | FLOAT32 | ABCD | % | Read | |||
| IR | 2658doc 32658 | Internal temperature | FLOAT32 | ABCD | °C | Read | |||
| IR | 2750doc 32750 | Active tariff (float) | FLOAT32 | ABCD | Read | ||||
| IR | 2752doc 32752 | Energy counter n1 | Non-resettable counter; quantity set by 40421/40422. | FLOAT32 | ABCD | Wh | Read | ||
| IR | 2754doc 32754 | Energy counter n2 | Non-resettable counter; quantity set by 40425/40426. | FLOAT32 | ABCD | varh | Read | ||
| IR | 2756doc 32756 | Energy counter n3 | Non-resettable counter; quantity set by 40429/40430. | FLOAT32 | ABCD | Wh | Read | ||
| IR | 2758doc 32758 | Energy counter n4 | Non-resettable counter; quantity set by 40433/40434. | FLOAT32 | ABCD | varh | Read | ||
| IR | 2760doc 32760 | Energy counter 1 | Resettable user counter; Wh, varh or VAh per its parameter 40437. | FLOAT32 | ABCD | Read | |||
| IR | 2762doc 32762 | Energy counter 2 | Resettable user counter; unit per its parameter 40441. | FLOAT32 | ABCD | Read | |||
| HR | 10doc 40010 | Active access level | 0 = full protection. | UINT16 | Read/write | ||||
| HR | 12doc 40012 | Operator command | UINT16 | Write | 1 = Save settings; 2 = Abort settings; 3 = Restart instrument; 4 = Restart Ethernet; 5 = Save settings and restart Ethernet | ||||
| HR | 15doc 40015 | IR external relay command | UINT16 | Read/write | 0 = Off; 1 = On | ||||
| HR | 30doc 40030 | Select active tariff | Tariff 1 to 6. | UINT16 | Read/write | ||||
| HR | 31doc 40031 | Reset energy counters | Set a bit to reset that resettable counter. | BITMAP16 | Write | bit 0 = Reset counter 1; bit 1 = Reset counter 2; bit 2 = Reset counter 3; bit 3 = Reset counter 4; bit 4 = Reset counter 5; bit 5 = Reset counter 6; bit 6 = Reset counter 7; bit 7 = Reset counter 8; bit 8 = Reset counter 9; bit 9 = Reset counter 10; bit 10 = Reset counter 11; bit 11 = Reset counter 12; bit 12 = Reset counter 13; bit 13 = Reset counter 14; bit 14 = Reset counter 15; bit 15 = Reset counter 16 | |||
| HR | 143doc 40143 | Connection mode | UINT16 | Read/write | 0 = No mode; 1 = 1b - single phase; 2 = 3b - 3-phase 3-wire balanced; 3 = 4b - 3-phase 4-wire balanced; 4 = 3u - 3-phase 3-wire unbalanced; 5 = 4u - 3-phase 4-wire unbalanced | ||||
| HR | 202doc 40202 | Port 1 Modbus address | 1 to 247. | UINT16 | Read/write | ||||
| HR | 203doc 40203 | Port 1 baud rate | UINT16 | Read/write | 0 = 1200; 1 = 2400; 2 = 4800; 3 = 9600; 4 = 19200; 5 = 38400; 6 = 57600; 7 = 115200 | ||||
| HR | 204doc 40204 | Port 1 stop bits | UINT16 | Read/write | 0 = 1 stop bit; 1 = 2 stop bits | ||||
| HR | 205doc 40205 | Port 1 parity | UINT16 | Read/write | 0 = None; 1 = Odd; 2 = Even | ||||
| HR | 419doc 40419 | Total energy calculation | UINT16 | Read/write | 0 = Sum of phases; 1 = Individual phases | ||||
| HR | 421doc 40421 | Energy counter n1 parameter | Quantity this counter integrates. | UINT16 | Read/write | 0 = No parameter; 1 = Active power; 2 = Reactive power; 3 = Apparent power; 5 = Active power phase 1; 6 = Reactive power phase 1; 7 = Apparent power phase 1; 9 = Active power phase 2; 10 = Reactive power phase 2; 11 = Apparent power phase 2; 13 = Active power phase 3; 14 = Reactive power phase 3; 15 = Apparent power phase 3; 33 = Active power individual phases; 34 = Reactive power individual phases; 35 = Apparent power individual phases | |||
| HR | 422doc 40422 | Energy counter n1 configuration | Which quadrants are counted; decides import vs export. | BITMAP16 | Read/write | bit 0 = Quadrant I enabled; bit 1 = Quadrant II enabled; bit 2 = Quadrant III enabled; bit 3 = Quadrant IV enabled; bit 4 = Absolute value; bit 5 = Invert value |
Notes on this map
- Wire address = printed number - 30000 (input registers) or - 40000 (holding registers); see the 30107 / 0x006B example in the document.
- T_float is IEEE 754 single precision sent high word first; the document's example stores 123.45 as 42F6 E666, so floats are ABCD. T3 (signed 32-bit) is also high word first.
- Measurements at 30105-30190 refresh once per second; the integer energy counters every 40 ms.
- Left out: the integer measurement block (30105-30175 and the 355xx-357xx average/max/min copies). It uses Finder types T5/T6/T7, which pack a signed decade exponent in the top byte and the value in the low 24 bits (or sign flags for power factor); that needs custom decoding rather than a plain integer with a fixed scale. Use the float block instead.
- Left out: integer energy counters 30406-30445 ('mantissa x EXP(exponent register)') because the document does not define the EXP operation, and the '1000 x energy counter' block, because the intro text places it at 30426-30441 while the table lists it at 30462-30501.
- Left out: a second float copy of counters n1-n4 at 32638-32645 that has no function code printed; the ENERGY block at 32752-32759 is used.
- Energy counters n1-n4 are non-resettable, counters 1-16 are user counters that can be reset via 40031. What each counter integrates (active/reactive/apparent, which phase, which quadrants = import or export) is set in the counter's parameter and configuration registers (40421 onward); the document does not list factory assignments, so check them on the meter.
- Left out: CAP/IND power factor floats (32562-32569) because the sign convention is not explained, alarm flag words, logic functions, data logger, LCD, Ethernet/WiFi/M-Bus settings and the alarm/pulse-output configuration groups.
- The 7M.24 single-phase meter uses a separate, shorter table in the same document and is not covered here.
- Verifier: the document does not name a specific order code for the RS485 version; it only says '7M.38.8.400.XXXX with serial communication'. The 0212 alias comes from Finder's catalogue, not this PDF.
Check it against the live device. A register map tells you what the controller can expose; the unit in front of you may differ by firmware or options. Read a few registers and compare them with the unit’s own display; for a 32-bit value the float and byte-order decoder shows all four word orders at once, so a wrong word order or scale is obvious. New to this? Read what a register map is and why addresses are off by one.
Questions about the Finder 7M.38 three-phase energy meter (Modbus RS485)
What Modbus registers does the Finder 7M.38 three-phase energy meter (Modbus RS485) have?
This map lists 72 registers: 59 input registers, 13 holding registers. 13 of them can be written. Registers vary with firmware, options and configuration, so confirm against the device.
Are the Finder 7M.38 three-phase energy meter (Modbus RS485) Modbus addresses 0-based or 1-based?
The manufacturer's document numbers registers Modicon 3xxxx/4xxxx (drop the prefix, subtract 1). Every address on this page is the 0-based wire address you put in the request; the documented number is shown under it where it differs. Registers are printed as 3xxxx (input, function 04) and 4xxxx (holding, functions 03/06/16), and the document gives 30000 / 40000 as the memory reference - not 30001. Its request example reads U1 (30107) by sending start address 0x006B = 107. So the wire address is the printed number minus 30000 or 40000: Pt float 32490 is input register 2490.
What byte order does the Finder 7M.38 three-phase energy meter (Modbus RS485) use for 32-bit values?
Multi-register values in this map use ABCD (high word first (big-endian)). Set your client to this order for every 32/64-bit value in the table.
What are the minimum Modbus registers to integrate the Finder 7M.38 three-phase energy meter (Modbus RS485)?
Start with IR 2500 U1 (U1 voltage (float, V)); IR 2516 I1 (I1 current (float, A)); IR 2490 Active power total (Pt) (Total active power (float, W)); IR 2496 Power factor total (PFt) (Total power factor); IR 2498 Frequency (Frequency); IR 2752 Energy counter n1 (Energy counter n1 (float, Wh)); IR 2756 Energy counter n3 (Energy counter n3 (float, Wh)).
How do I enable Modbus control of the Finder 7M.38 three-phase energy meter (Modbus RS485)?
Modbus RTU runs on the RS485 serial versions (7M.38.8.400.XXXX). Port 1 address, baud, stop bits and parity sit in registers 40202-40205; writing settings needs the access level raised first by writing the user password to 40001 (function 16), then save with operator command 40012 = 1.
Where is the official Finder 7M.38 three-phase energy meter (Modbus RS485) Modbus documentation?
The source is Modbus Communication Protocol 7M24 - 7M38 (v2 (footer 07/2026)), revision 07/2026, published free by Finder at https://cdn.findernet.com/app/uploads/Modbus-7M24-7M38_v2_30062021.pdf.
Source: Modbus Communication Protocol 7M24 - 7M38 · v2 (footer 07/2026) · rev. 07/2026. Register numbers, types, scaling and units are reproduced as published; descriptions are our own.