Tables of Contents

Setup Information

The following list indicates important setup information for running in Modbus TCP. Ensure that the master is setup with the same configuration.

  • Port 502 - Modbus-TCP uses port 502. This is fixed.
  • Holding register addressing depends on the system used. Refer to your modbus master documentation to understand the address format.
    • Additional information is below to list the most common address types
  • Max holding registers for read and write is 16
  • Use function code 0x10 for write single register. Function code 0x06 is not supported.
  • All registers are 32-bit
    • Exceptions are the registers used used directly in the CM1-T Library (IEC 61131-3).
  • 32-bit word mapping is little endian

Holding Register List


Included below is a table which details the location and function of the CM1 Modbus registers.
The addresses included below are referenced to the Modbus data model (PLC address for read/write to holding registers)

Note: Even if Direct Control is not used the Direct Control feedback registers can be useful for reading back motor information.

Click on a link below to jump to the associated registers


Motor Information

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

0

40001

Position Error (?95)

Yes

No

2

40003

Motor Position (?96)

Yes

No

4

40005

Motor Speed (?97)

Yes

No

6

40007

Motor Torque (?98)

Yes

No

8

40009

Motor Status (?99)

Yes

No

Variables

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

10

40011

V0

Yes

Yes

12

40013

V1

Yes

Yes

14

40015

V2

Yes

Yes

16

40017

V3

Yes

Yes

18

40019

V4

Yes

Yes

20

40021

V5

Yes

Yes

22

40023

V6

Yes

Yes

24

40025

V7

Yes

Yes

26

40027

V8

Yes

Yes

28

40029

V9

Yes

Yes

30

40031

V10

Yes

Yes

32

40033

V11

Yes

Yes

34

40035

V12

Yes

Yes

36

40037

V13

Yes

Yes

38

40039

V14

Yes

Yes

40

40041

V15

Yes

Yes

Direct Registers

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

42

40043

P0

Yes

Yes

44

40045

S0

Yes

Yes

46

40047

A0

Yes

Yes

48

40049

V0

Yes

Yes

50

40051

R0

Yes

Yes

52

40053

M0

Yes

Yes

Inputs/Outputs

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

54

40055

Analog Output

Yes

Yes

56

40057

Input Status (?70)

Yes

No

58

40059

Output Status (?50)

Yes

Yes

Positions

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

200

40201

P0

Yes

Yes

202

40203

P1

Yes

Yes

204

40205

P2

Yes

Yes

206

40207

P3

Yes

Yes

208

40209

P4

Yes

Yes

210

40211

P5

Yes

Yes

212

40213

P6

Yes

Yes

214

40215

P7

Yes

Yes

216

40217

P8

Yes

Yes

218

40219

P9

Yes

Yes

220

40221

P10

Yes

Yes

222

40223

P11

Yes

Yes

224

40225

P12

Yes

Yes

226

40227

P13

Yes

Yes

228

40229

P14

Yes

Yes

230

40231

P15

Yes

Yes

232

40233

P16

Yes

Yes

234

40235

P17

Yes

Yes

236

40237

P18

Yes

Yes

238

40239

P19

Yes

Yes

240

40241

P20

Yes

Yes

242

40243

P21

Yes

Yes

244

40245

P22

Yes

Yes

246

40247

P23

Yes

Yes

248

40249

P24

Yes

Yes

250

40251

P25

Yes

Yes

R Registers

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

300

40301

R0

Yes

Yes

302

40303

R1

Yes

Yes

304

40305

R2

Yes

Yes

306

40307

R3

Yes

Yes

308

40309

R4

Yes

Yes

310

40311

R5

Yes

Yes

312

40313

R6

Yes

Yes

314

40315

R7

Yes

Yes

316

40317

P8

Yes

Yes

318

40319

P9

Yes

Yes

320

40321

R10

Yes

Yes

322

40323

R11

Yes

Yes

324

40325

R12

Yes

Yes

326

40327

R13

Yes

Yes

328

40329

R14

Yes

Yes

330

40331

R15

Yes

Yes

332

40333

R16

Yes

Yes

334

40335

R17

Yes

Yes

336

40337

R18

Yes

Yes

338

40339

R19

Yes

Yes

340

40341

R20

Yes

Yes

342

40343

R21

Yes

Yes

344

40345

R22

Yes

Yes

346

40347

R23

Yes

Yes

348

40349

R24

Yes

Yes

350

40351

R25

Yes

Yes

N Registers

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

400

40401

N0

Yes

Yes

402

40403

N1

Yes

Yes

404

40405

N2

Yes

Yes

406

40407

N3

Yes

Yes

408

40409

N4

Yes

Yes

410

40411

N5

Yes

Yes

412

40413

N6

Yes

Yes

414

40415

N7

Yes

Yes

416

40417

N8

Yes

Yes

418

40419

N9

Yes

Yes

420

40421

N10

Yes

Yes

422

40423

N11

Yes

Yes

424

40425

N12

Yes

Yes

426

40427

N13

Yes

Yes

428

40429

N14

Yes

Yes

430

40431

N15

Yes

Yes

432

40433

N16

Yes

Yes

434

40435

N17

Yes

Yes

436

40437

N18

Yes

Yes

438

40439

N19

Yes

Yes

440

40441

N20

Yes

Yes

442

40443

N21

Yes

Yes

444

40445

N22

Yes

Yes

446

40447

N23

Yes

Yes

448

40449

N24

Yes

Yes

450

40451

N25

Yes

Yes

Speeds

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

602

40603

S0

Yes

Yes

604

40605

S1

Yes

Yes

606

40607

S2

Yes

Yes

608

40609

S3

Yes

Yes

610

40611

S4

Yes

Yes

612

40613

S5

Yes

Yes

614

40615

S6

Yes

Yes

616

40617

S7

Yes

Yes

618

40619

S8

Yes

Yes

620

40621

S9

Yes

Yes

622

40623

S10

Yes

Yes

624

40625

S11

Yes

Yes

626

40627

S12

Yes

Yes

628

40629

S13

Yes

Yes

630

40631

S14

Yes

Yes

632

40633

S15

Yes

Yes

Accelerations

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

634

40635

A0

Yes

Yes

636

40637

A1

Yes

Yes

638

40639

A2

Yes

Yes

640

40641

A3

Yes

Yes

642

40643

A4

Yes

Yes

644

40645

A5

Yes

Yes

646

40647

A6

Yes

Yes

648

40649

A7

Yes

Yes

650

40651

A8

Yes

Yes

Torques

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

652

40653

M0

Yes

Yes

654

40655

M1

Yes

Yes

656

40657

M2

Yes

Yes

658

40659

M3

Yes

Yes

660

40661

M4

Yes

Yes

662

40663

M5

Yes

Yes

664

40665

M6

Yes

Yes

666

40667

M7

Yes

Yes

668

40669

M8

Yes

Yes

K Parameters

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

670

40671

RESERVED

Yes

No

672

40673

K1

Yes

No

674

40675

K2

Yes

No

676

40677

K3

Yes

No

678

40679

K4

Yes

No

680

40681

K5

Yes

No

682

40683

K6

Yes

No

684

40685

K7

Yes

No

686

40687

K8

Yes

No

688

40689

K9

Yes

No

690

40691

K10

Yes

No

692

40693

K11

Yes

No

694

40695

K12

Yes

No

696

40697

K13

Yes

No

698

40699

K14

Yes

No

700

40701

K15

Yes

No

702

40703

K16

Yes

No

704

40705

K17

Yes

No

706

40707

K18

Yes

No

708

40709

K19

Yes

No

710

40711

K20

Yes

Yes

712

40713

K21

Yes

Yes

714

40715

K22

Yes

Yes

716

40717

K23

Yes

Yes

718

40719

K24

Yes

Yes

720

40721

K25

Yes

Yes

722

40723

K26

Yes

Yes

724

40725

K27

Yes

Yes

726

40727

K28

Yes

Yes

728

40729

K29

Yes

Yes

730

40731

K30

Yes

Yes

732

40733

K31

Yes

Yes

734

40735

K32

Yes

Yes

736

40737

K33

Yes

Yes

738

40739

K34

Yes

Yes

740

40741

K35

Yes

Yes

742

40743

K36

Yes

Yes

744

40745

K37

Yes

Yes

746

40747

K38

Yes

Yes

748

40749

K39

Yes

Yes

750

40751

K40

Yes

Yes

752

40753

K41

Yes

Yes

754

40755

K42

Yes

Yes

756

40757

K43

Yes

Yes

758

40759

K44

Yes

Yes

760

40761

K45

Yes

Yes

762

40763

K46

Yes

Yes

764

40765

K47

Yes

Yes

766

40767

K48

Yes

Yes

768

40769

K49

Yes

Yes

770

40771

K50

Yes

Yes

772

40773

K51

Yes

Yes

774

40775

K52

Yes

Yes

776

40777

K53

Yes

Yes

778

40779

K54

Yes

Yes

780

40781

K55

Yes

Yes

782

40783

K56

Yes

Yes

784

40785

K57

Yes

Yes

786

40787

K58

Yes

Yes

788

40789

K59

Yes

Yes

790

40791

K60

Yes

Yes

792

40793

K61

Yes

Yes

794

40795

K62

Yes

Yes

796

40797

K63

Yes

Yes

798

40799

K64

Yes

Yes

800

40801

K65

Yes

Yes

802

40803

K66

Yes

Yes

804

40805

K67

Yes

Yes

806

40807

K68

Yes

Yes

808

40809

K69

Yes

Yes

810

40811

K70

Yes

Yes

812

40813

K71

Yes

Yes

814

40815

K72

Yes

Yes

816

40817

K73

Yes

Yes

818

40819

K74

Yes

Yes

820

40821

K75

Yes

Yes

822

40823

K76

Yes

Yes

824

40825

K77

Yes

Yes

826

40827

K78

Yes

Yes

828

40829

K79

Yes

Yes

830

40831

K80

Yes

Yes

832

40833

K81

Yes

Yes

834

40835

K82

Yes

Yes

836

40837

K83

Yes

Yes

838

40839

K84

Yes

Yes

840

40841

K85

Yes

Yes

842

40843

K86

Yes

Yes

844

40845

K87

Yes

Yes

846

40847

K88

Yes

Yes

848

40849

K89

Yes

Yes






874

40875

RESERVED

No

Yes

H Gain Parameters

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

900

40901

H0

Yes

Yes

902

40903

H1

Yes

Yes

904

40905

H2

Yes

Yes

906

40907

H3

Yes

Yes

908

40909

H4

Yes

Yes

910

40911

H5

Yes

Yes

912

40913

H6

Yes

Yes

914

40915

H7

Yes

Yes

Timers

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

950

40951

T0

Yes

No

952

40953

T1

Yes

Yes

954

40955

T2

Yes

Yes

956

40957

T3

Yes

Yes

958

40959

T4

Yes

Yes

960

40961

T5

Yes

Yes

962

40963

T6

Yes

Yes

964

40965

T7

Yes

Yes

96640967T8YesYes

Direct Control Registers

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

100041001CPUTimeYesNo
100241003ActualPositionYesNo
100441005ActualTargetPositionYesNo
100641007MotorStatusYesNo
100841009ActualRatedCurrentYesNo
101041011ActualOverloadTorqueYesNo
101241013AnalogInYesNo
101441015DigitalInYesNo
101641017TemperatureYesNo
101841019DCVoltageYesNo
102041021N/AYesNo
102241023ModeOfOperationDisplayYesNo
102441025N/AYesNo
102641027ActualSpeedYesNo
102841029TargetPositionYesYes
103041031TargetSpeedYesYes
103241033TargetTorqueYesYes
103441035TargetAccelerationYesYes
103641037TargetDecelerationYesYes
103841039ControlwordYesYes
104041041ModeOfOperationYesYes
104241043DigitalOutYesYes

CM1-T Library Mapped Registers

The set of registers below are typically used when mapping the Modbus read and write messages directly to a data structure.

  • This is often achieved using function code 0x23 (read/write in single message)
  • The data structure should break the DINT register into the respective variables.
  • The CM1-T Library has been developed to be used with IEC 61131-3 IDEs such as Codesys, Machine Expert and TwinCAT. See Examples and Demos.

Holding Register Address

Motor Parameter


Read Access


Write Access


Base Address

Modicon Address

Read Registers
110041101us50Counter (DINT)YesNo
110241103ActualPosition (DINT)YesNo
110441105MotionTarget (DINT)YesNo
110641107ActualVelocity (DINT)YesNo
110841109

MotorStatus (INT)

PercentActualCurrent (INT)

YesNo
111041111

PercentOverloadTorque (INT)

AnalogIN (INT)

YesNo
111241113

DCVoltage (INT)

DigitalIO (SINT)

Temperature (SINT)

YesNo
111441115

ModeOfOperationDisplay (SINT)

ErrorCode (SINT)

ReadAddress1 (INT)

YesNo
111641117ReadValue1 (DINT)YesNo
Write Registers
120041201TargetPosition (DINT)YesYes
120241203TargetVelocity (DINT)YesYes
120441205

TargetTorque (INT)

TargetAcceleration (INT)

YesYes
120641207

TargetDeceleration (INT)

ControlWord (INT)

YesYes
120841209

ModeOfOperation (SINT)

DigitalOUT (SINT)

WriteAddress1 (INT)

YesYes
121041211WriteValue1 (DINT)YesYes
121241213

ReadAddress1 (INT)

PAD (INT)

YesYes