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Danfoss VLT Micro Drive FC 51 Modbus register map

VLT Micro Drive FC 51 over the built-in RS485 port, Modbus RTU with the FC control profile

  • Official
  • 95 registers
  • Modbus RTU
  • Revision 1 · 2026-11-10

Official: Written from the manufacturer's documentation, but not tested on a device yet. Check the map against the manufacturer's documentation before you write to a live device. Tested it? Report a test.

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Communication

Protocol
Modbus RTU
Unit ID
1
Serial
19200 8E1 · 19200 baud, 8 data bits, even parity, 1 stop bit
Byte / word order
ABCD · bytes big-endian, words high first
Addresses
1-based · wire address = address − 1

Connection values are defaults: the device may be configured differently.

Map

Registers
95 holding registers
Groups
10
Translation tables
6
Revision
1 · 2026-11-10
Added
()
File
maps/danfoss/fc-51.mbmap.json · 20 KB · history
SHA-256
ed9e7e22c189e55b0ff1949a086e8a9502567225af753a91b38bc6271dbbc0f6
Manufacturer
danfoss.com

Sources and notes

Source: Danfoss, "VLT Micro Drive FC 51 Design Guide", MG02K402 (01/2016) and "VLT Micro Drive FC 51 Programming Guide", MG02C602 (software 2.7X)

  • Holding register of parameter x-yy is 10 times its number: 3-41 is register 3410, 16-14 is register 16140, 8-30 is register 8300. The guide counts registers from 1 and the bus address is one less, so this map uses address_base 1.
  • Control word, bus reference, status word and main actual value are registers 50000, 50010, 50200 and 50210. From software 2.32 they are also at 2810, 2811, 2910 and 2911.
  • Array parameters (3-10, 15-30) need the index in register 9 first. A 32-bit parameter uses two registers, high word first. One-byte parameters are read and written as one register.
  • Coil 65 chooses whether written parameters go to RAM only (0) or to RAM and EEPROM (1). Coils 1 to 64 repeat the control word, reference, status word and output frequency; they are not in this map, use the registers instead.
  • To enable Modbus: 8-30 Protocol = Modbus RTU, 8-31 Address 1 to 247, 8-32 baud rate, 8-33 parity. The guide gives even parity with 1 stop bit as the default; the Programming Guide lists 19200 baud as the Modbus default.
  • The guide's text for 8-32 allows up to 115200 baud, while the Programming Guide for software 2.7X lists 2400 to 38400. Only the Programming Guide values are in the table.
  • The Design Guide is for software 3.1X and the Programming Guide for 2.7X; conversion indexes are taken from the latter. Some Programming Guide parameters (motor power 1-20, text parameters such as 15-43 and 15-51) are not listed, as no size or scaling is given.
  • Function codes: 1, 3, 5, 6, 15 and 16, plus 11, 17 and the diagnostics function 8.
  • Written from the manufacturer's documents; not tested on a device.
AreaAddressNameTypeAccessUnitScaleDescription
HR 7 uint16 R Fault code last returned by the parameter database
HR 8 uint16 R Address of the register that caused the last error
HR 9 uint16 RW Index used for the next access to an array parameter (for example 3-10 or 15-30); set it before reading or writing one
HR 50000 uint16 RW FC profile control word (8-10 Control Word Profile = FC profile)
HR 50000 uint16 bits 0–1 RW Chooses one of the four values of 3-10 Preset Reference (bits 0 and 1)
HR 50000 bool bit 2 RW 0 = DC brake and stop, 1 = ramp
HR 50000 bool bit 3 RW 0 = coast to a stop, 1 = no coasting
HR 50000 bool bit 4 RW 0 = quick stop, 1 = ramp
HR 50000 bool bit 5 RW 0 = hold the present output frequency, 1 = use the ramp
HR 50000 bool bit 6 RW 0 = ramp stop, 1 = start
HR 50000 bool bit 7 RW Reset a trip on the rising edge
HR 50000 bool bit 8 RW 1 = run at the jog speed (3-11)
HR 50000 bool bit 9 RW 0 = ramp 1, 1 = ramp 2
HR 50000 bool bit 10 RW 1 = the drive uses the control word, 0 = it ignores it
HR 50000 bool bit 11 RW 1 = relay 01 on, if 5-40 Function Relay selects control word bit 11
HR 50000 bool bit 12 RW 1 = relay 02 on, if 5-40 Function Relay selects control word bit 12
HR 50000 bool bit 13 RW 0 = set-up 1, 1 = set-up 2 (only with 0-10 Active Set-up = Multi set-up)
HR 50000 bool bit 15 RW 1 = reverse (acts only if 8-54 Reversing Select allows the bus)
HR 50010 int16 RW % ×0.006103515625 Speed reference in percent of the maximum reference (3-03): 16384 (4000 hex) = 100%, negative values in two's complement. Scale is 100/16384
HR 50200 uint16 R FC profile status word
HR 50200 bool bit 0 R 0 = control not ready, 1 = control ready
HR 50200 bool bit 1 R 0 = not ready, 1 = ready for operation
HR 50200 bool bit 2 R 0 = coasting, 1 = enabled
HR 50200 bool bit 3 R 1 = the drive has tripped
HR 50200 bool bit 4 R 1 = error without a trip
HR 50200 bool bit 6 R 1 = tripped and locked
HR 50200 bool bit 7 R 1 = a warning is active
HR 50200 bool bit 8 R 0 = speed differs from the reference, 1 = speed matches the reference
HR 50200 bool bit 9 R 0 = local operation, 1 = the drive can be controlled over the bus
HR 50200 bool bit 10 R 0 = output frequency at a speed limit (4-12 or 4-14), 1 = within limits
HR 50200 bool bit 11 R 0 = motor not running, 1 = in operation
HR 50200 bool bit 12 R 1 = stopped for temporary overtemperature, resumes by itself
HR 50200 bool bit 13 R 1 = DC link voltage too low or too high
HR 50200 bool bit 14 R 1 = the current limit is exceeded
HR 50200 bool bit 15 R 1 = a motor or drive thermal timer has passed 100%
HR 50210 int16 R % ×0.006103515625 Actual output frequency, scaled like the bus reference: 16384 (4000 hex) = 100%. Scale is 100/16384
HR 2810 uint16 RW Same control word as register 50000, in the lower register area (software 2.32 and later)
HR 2811 int16 RW % ×0.006103515625 Same bus reference as register 50010 (16384 = 100%), lower register area (software 2.32 and later)
HR 2910 uint16 R Same status word as register 50200, lower register area (software 2.32 and later)
HR 2911 int16 R % ×0.006103515625 Same main actual value as register 50210 (16384 = 100%), lower register area (software 2.32 and later)
HR 16010 int32 ABCD R ×0.001 Present reference in the unit of the configuration (Hz in open loop)
HR 16020 int16 R % ×0.1
HR 16050 int16 R % ×0.01
HR 16100 uint16 R kW ×0.001
HR 16110 uint16 R hp ×0.001
HR 16120 uint16 R V
HR 16130 uint16 R Hz ×0.1
HR 16140 uint16 R A ×0.01
HR 16150 uint16 R % ×0.1
HR 16180 uint16 R % Calculated thermal load of the motor; 100% is the cutout limit. The parameter is one byte, read as a register
HR 16300 uint16 R V
HR 16340 uint16 R °C One-byte parameter, read as a register
HR 16350 uint16 R % One-byte parameter, read as a register
HR 16360 uint16 R A ×0.01
HR 16370 uint16 R A ×0.01
HR 16600 uint16 R Bit pattern of the digital inputs
HR 16620 uint16 R V ×0.01
HR 16630 uint16 R mA ×0.01
HR 16640 uint16 R mA ×0.01
HR 16650 uint16 R mA ×0.01
HR 16710 uint16 R Bit pattern of the relay outputs; one-byte parameter, read as a register
HR 16900 uint32 ABCD R Alarm word as a bit pattern (bits are in the Programming Guide)
HR 16920 uint32 ABCD R Warning word as a bit pattern (bits are in the Programming Guide)
HR 16940 uint32 ABCD R
HR 15000 uint32 ABCD R days Days the drive has been powered up
HR 15010 uint32 ABCD R h
HR 15020 uint32 ABCD R kWh
HR 15030 uint32 ABCD R
HR 15040 uint16 R
HR 15050 uint16 R
HR 15300 uint16 R Array of the last trips; set the index in register 9 first (one-byte parameter, read as a register)
HR 1220 uint16 RW V
HR 1230 uint16 RW Hz
HR 1240 uint16 RW A ×0.01
HR 1250 uint16 RW RPM
HR 3020 int32 ABCD RW ×0.001
HR 3030 int32 ABCD RW ×0.001
HR 3100 int16 RW % ×0.01 Array of 8 values; set the index in register 9 first
HR 3110 uint16 RW Hz ×0.1
HR 3410 uint32 ABCD RW s ×0.01
HR 3420 uint32 ABCD RW s ×0.01
HR 3510 uint32 ABCD RW s ×0.01
HR 3520 uint32 ABCD RW s ×0.01
HR 4120 uint16 RW Hz ×0.1
HR 4140 uint16 RW Hz ×0.1
HR 4160 uint16 RW %
HR 4170 uint16 RW %
HR 8010 uint16 RW One-byte parameter, written as a register
HR 8020 uint16 RW
HR 8030 uint16 RW s ×0.1
HR 8040 uint16 RW
HR 8300 uint16 RW Takes effect after the drive is powered off and on
HR 8310 uint16 RW
HR 8320 uint16 RW
HR 8330 uint16 RW

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